Gas Mileage Question

I was just wondering what kind of mileage everyone gets on their car. My 96 Roady with 2:93 (I think) is getting just over 14mpg combined city/highway. I was hoping for a little more. What are you guys getting, and what do you think I should get pure highway when I drive to Florida next month?

We were getting 24 mpg highway before I put in a more free-flowing exhaust and a Brian Herter tune. Then it got worse. On our most recent vacation, I tracked the mileage between fills. We sometimes got 22 mpg, and sometimes 19 mpg.

Mark,do you know what the ethanol level is there and are others around you having mileage
issues?Is anyone else driving it and how is your AC cooling?Are you doing a lot of idling?
Eliminate the easy possibilitys first.

Mark 96 Roady wrote:

I was just wondering what kind of mileage everyone gets on their car. My 96 Roady with 2:93 (I think) is getting just over 14mpg combined city/highway. I was hoping for a little more. What are you guys getting, and what do you think I should get pure highway when I drive to Florida next month?

Yikes, unless you can't keep your foot out of it, thats really low.

My '93 Gets 16 city and about 22-23 highway for a combined of 19-22. Our Fleetwood at work gets about 23 highway even with me doing 75.

I get a combined 16.5-17 mpg pretty consistently on my 226,000 mile, 1994, 2.93 rear, BRMW mostly going to and from work, 17.5 miles each way. I got 23 mpg 2 summers ago with just me and shirlock9C1 in the car going to Irwin, NY., about 90 miles each way, and all expressway. Keep 'em tuned up, keep your foot out of it, and use cruise.

Mike

At 450 hp, I'm lucky to hit 10mph on a good day around the neighbor hood. I actually hit 16 during Wagonfest weekend.

One of the tradeoffs of being able to fry tires.

My 96 tow-package Roady got around 16-18 in normal daily driving and I got into the mid-20's with the cruise set on road trips. I loved it, it could haul almost as much as my wife's Suburban but got a LOT better mpg.

Do the usual things. Air up your tires, change your air filter, replace the fuel filter, and go easy on start and stop, and I bet you'll see an improvement.

-Mike

Wow- I'm kinda concerned at what we are getting gas mileage wise. My wife and I both are very conservative drivers-easy starts, brakes, etc. The last 2 tanks were about 30% highway, rest city stop and go. I use regular unleaded, not sure what the ethanol level is. Since it's summer, of course the air is on. No cargo in the car, usually just her or sometimes the two of us. It runs fine, but of course I have no way of knowing if it has ever been tuned up. The air filter is new, and it has a new oil change. I have not checked the tire air pressure, but I will tomorrow, but they look fine. The first tank was 14.5, this last one 14.1. Do you need to take off the front wheels to get at the spark plugs on both sides? They don't look like much fun to get to. If they are original, I'm wondering if that could be the problem.

70mph on 10% ethanol blend and 213k miles... 21.7 at 90% highway miles.

Quote :

The last 2 tanks were about 30% highway, rest city stop and go. I use regular unleaded, not sure what the ethanol level is. Since it's summer, of course the air is on. No cargo in the car, usually just her or sometimes the two of us. It runs fine, but of course I have no way of knowing if it has ever been tuned up. The air filter is new, and it has a new oil change. I have not checked the tire air pressure, but I will tomorrow, but they look fine. The first tank was 14.5, this last one 14.1. Do you need to take off the front wheels to get at the spark

If your getting 14.5 mpg with 70% city stop and go that is about normal.
City driving is a gas guzzle because the engine is running when you are at a stop and that meams 0 mpg .
When you accelerate from a stop to 35 mph its getting 3-5 mpg .
When driving at 35 mph its getting about 20-25mpg .
So depending on how long you are at a stop and how many times you have to accelerate has a big impact om mpg.
I live in florida and in my 96 RMW I typically get 15 mpg driving around town and 21 mpg on interstate with AC running
Thats with 3.08 gears and 18" tires
With stock gears and 15" tires should do 1-2 mpg better on highway .

That's pretty much what I was going to offer up as well. The more stop lights you hit on the way to work the worse it's going to be. Bumper to bumper in rush hour is no different as it's crawl, stop, crawl, stop, but the engine keeps running.

Half the time my convertor never gets a chance to lock up as I'm below the programmed MPH required for it to occur.That's another big dent in the MPG's there as well.

lakeffect wrote:

At 450 hp, I'm lucky to hit 10mph on a good day around the neighbor hood. I actually hit 16 during Wagonfest weekend.

One of the tradeoffs of being able to fry tires.

I've got half your horsepower and I drive around the neighborhood a lot faster than that, maybe 25 - 30 mph.

... but I can get to 22 mph REALLY FAST

(I meant to type 10 MPG not 10 MPH ... and 16 mpg during WF12...oops)

etsfl wrote:

Quote :

The last 2 tanks were about 30% highway, rest city stop and go. I use regular unleaded, not sure what the ethanol level is. Since it's summer, of course the air is on. No cargo in the car, usually just her or sometimes the two of us. It runs fine, but of course I have no way of knowing if it has ever been tuned up. The air filter is new, and it has a new oil change. I have not checked the tire air pressure, but I will tomorrow, but they look fine. The first tank was 14.5, this last one 14.1. Do you need to take off the front wheels to get at the spark

If your getting 14.5 mpg with 70% city stop and go that is about normal.
City driving is a gas guzzle because the engine is running when you are at a stop and that meams 0 mpg .
When you accelerate from a stop to 35 mph its getting 3-5 mpg .
When driving at 35 mph its getting about 20-25mpg .
So depending on how long you are at a stop and how many times you have to accelerate has a big impact om mpg.
I live in florida and in my 96 RMW I typically get 15 mpg driving around town and 21 mpg on interstate with AC running
Thats with 3.08 gears and 18" tires
With stock gears and 15" tires should do 1-2 mpg better on highway .

[b]where in florida are you located

DROLDS2U wrote:

etsfl wrote:

Quote :

The last 2 tanks were about 30% highway, rest city stop and go. I use regular unleaded, not sure what the ethanol level is. Since it's summer, of course the air is on. No cargo in the car, usually just her or sometimes the two of us. It runs fine, but of course I have no way of knowing if it has ever been tuned up. The air filter is new, and it has a new oil change. I have not checked the tire air pressure, but I will tomorrow, but they look fine. The first tank was 14.5, this last one 14.1. Do you need to take off the front wheels to get at the spark

If your getting 14.5 mpg with 70% city stop and go that is about normal.
City driving is a gas guzzle because the engine is running when you are at a stop and that meams 0 mpg .
When you accelerate from a stop to 35 mph its getting 3-5 mpg .
When driving at 35 mph its getting about 20-25mpg .
So depending on how long you are at a stop and how many times you have to accelerate has a big impact om mpg.
I live in florida and in my 96 RMW I typically get 15 mpg driving around town and 21 mpg on interstate with AC running
Thats with 3.08 gears and 18" tires
With stock gears and 15" tires should do 1-2 mpg better on highway .

[b]where in florida are you located

I'm in Fort Myers Beach on the Gulf coast. We spend about 4-5 months a year there, the rest in Pittsburgh.

Mark, i know where you are, i was asking the new guy...ETSFL , your roadie is beautiful, love those DCM cars

If you guys haven't done so yet, put yourselves on the forum map by going to the following thread.

https://gmlongroof.4umer.com/t6619-longroof-locator-powered-by-google-maps

Quote :

Mark, i know where you are, i was asking the new guy...ETSFL , your roadie is beautiful, love those DCM cars

Not a new guy. Been on this forum for many years , just don't post much unless it can be helpful .
Car has been in east central florida near Daytona Beach all of its life.
Thanks for the compliment.
Have a bunch of pictures at https://s151.photobucket.com/albums/s145/etsfl/1996%20RMW/

Mark, I'm getting about the same as you too. I've been using an injector cleaner and have seen an increase of .5mpgs.... so that helped a little bit. I'm a pretty moderate driver too, no fast starts or stops, but my 12 mile one way commute varies with 60mph to 30mph and a bunch of stop lights & signs. So overall I get about 15mpg.

etsfl wrote:

Quote :

Mark, i know where you are, i was asking the new guy...ETSFL , your roadie is beautiful, love those DCM cars

Not a new guy. Been on this forum for many years , just don't post much unless it can be helpful .
Car has been in east central florida near Daytona Beach all of its life.
Thanks for the compliment.
Have a bunch of pictures at https://s151.photobucket.com/albums/s145/etsfl/1996%20RMW/

Hey guys, check out these photos-his car is really beautiful. I especially like the hood ornament delete along with the partially painted grill. Very sharp!

Mark 96 Roady wrote:

etsfl wrote:

Quote :

Mark, i know where you are, i was asking the new guy...ETSFL , your roadie is beautiful, love those DCM cars

Not a new guy. Been on this forum for many years , just don't post much unless it can be helpful .
Car has been in east central florida near Daytona Beach all of its life.
Thanks for the compliment.
Have a bunch of pictures at https://s151.photobucket.com/albums/s145/etsfl/1996%20RMW/

Hey guys, check out these photos-his car is really beautiful. I especially like the hood ornament delete along with the partially painted grill. Very sharp!

MAN... you aint kidding!! That thing is BEAUTIFUL!!!

Well... I filled up this last Friday and FINALLY achieved 20mpg!! I've been using Lucas Injector Cleaner, keeping my foot out of the loud pedal and using cruise.

Mark 96 Roady wrote:

I was just wondering what kind of mileage everyone gets on their car. My 96 Roady with 2:93 (I think) is getting just over 14mpg combined city/highway. I was hoping for a little more. What are you guys getting, and what do you think I should get pure highway when I drive to Florida next month?

My '93 Caprice wagon with am LO5 350 and 2.73 rear end gears has been managing between 21 and 23 miles per gallon. I've only filled it with fuel twice now since acquiring it and nearly all driving has been highway. I usually drive around 60 MPH and the air conditioning is almost always on. I use my cruise control a LOT now that I have it working.

Gasoline pumps around here claim that up to 10% ethanol may be added to the product. I don't know if it actually is or not. I'd guess that it is.

I got slightly worse mileage after changing the old, filthy air filter out. Of course, I also let the car do some idling. Right now I have an exhaust leak that is causing the engine to run richer than it should.

uxwbill wrote:

Mark 96 Roady wrote:

I was just wondering what kind of mileage everyone gets on their car. My 96 Roady with 2:93 (I think) is getting just over 14mpg combined city/highway. I was hoping for a little more. What are you guys getting, and what do you think I should get pure highway when I drive to Florida next month?

My '93 Caprice wagon with am LO5 350 and 2.73 rear end gears has been managing between 21 and 23 miles per gallon. I've only filled it with fuel twice now since acquiring it and nearly all driving has been highway. I usually drive around 60 MPH and the air conditioning is almost always on. I use my cruise control a LOT now that I have it working.

Gasoline pumps around here claim that up to 10% ethanol may be added to the product. I don't know if it actually is or not. I'd guess that it is.

I got slightly worse mileage after changing the old, filthy air filter out. Of course, I also let the car do some idling. Right now I have an exhaust leak that is causing the engine to run richer than it should.

I like your Caprice. Have not seen larger pics of it. I see you're in Ill. Does the car have any rust? Looks clean in the small pics I've seen.

Oh and since you mentioned it, how do your replace the air filter on a TBI car? The Custom Cruiser will be my first non-LT1, and I've never touched one of those square airboxes before. Is there a traditional roundair filter element hiding in there? I want to check it before heading back to Texas from N Carolina.

-Mike

81X11 wrote:

I like your Caprice. Have not seen larger pics of it. I see you're in Ill. Does the car have any rust? Looks clean in the small pics I've seen.

I've got bigger pictures here. They are "hot off my digital camera" with no editing (or very little, as in image rotation) and coming from a server living in my basement on my broadband connection. As such, it's not a crazy fast server.





Forgive the lousy quality, these are frame grabs from my test drive video. I have some other videos here that might be worth a watch, if you want to see the underside of the car and the work my brother and I have done so far.

Yes, the car has some rust on the rear quarters. It's much worse on the passenger's side than the drivers and the spare tire carrier has partially succumbed to rust. If it weren't for that, the car would be perfect. I have plans to fix it all up when finances allow. Right now I've got to work on the climate control, get the radio repaired, install front brake pads and new rotors, put a new muffler on, and find out what is going "clunk" in the front end when I hit certain bumps. I also have one rear window to put a new roller in.

This car is in great shape for an Illinois car. I've had it up on a lift. The frame, floorpans and various other things on the underside are strong. They're not "eat off of this clean" like a southern car, but they're excellent for nearly twenty years of age. I gave $1700 for the car excluding tax, title and license fees.

81X11 wrote:

Oh and since you mentioned it, how do your replace the air filter on a TBI car? The Custom Cruiser will be my first non-LT1, and I've never touched one of those square airboxes before. Is there a traditional roundair filter element hiding in there? I want to check it before heading back to Texas from N Carolina.

There are two clips that you can see on top of the air box. These are springy metal tabs that will pop loose and then you can pivot the top of the airbox downward. Watch for the hose coming from the exhaust manifold and free it by hand. Tabs in the bottom of the air box hold the bottom part on. You can basically pivot it open like you were opening a door downwards and then carefully lift it free.

The air cleaner element is a rectangular thing that fits between the two halves of the air cleaner body. When I took my old air cleaner to NAPA for a replacement, the guys there said they'd never seen anything like it. They also had to order one. Cost was around $6 for a basic filter.

You put the new air filter into the part of the air box that stays on the engine. Then you put the bottom part of the air box into place so that the tabs match up with the holes, reconnect the tube coming from the exhaust manifold and flip the top of the box shut. Once it's seated, you can re-secure the clips. You may have to hold the two halves together while you fasten the clips.

Edit: Since a picture's worth a thousand words...

Thanks for all the pics and info! I really want the 5.7 decal for my car...mine's missing.

Looks like you have a really clean low-mile car there. Too bad about the 1/4 panels....I HATE salt!! The rest looks fine though, and the interior is CLEAN.

Good luck with it, and will check out your videos at home. Very cool!

-Mike

The curse about gas mileage is the same as the curse about deals - people only post about great deals or great gas mileage. Everyone else who gets a regular deal or regular gas mileage then feels bad.

I have a '94 RMW with 2.93 posi, stockish wheels/tires, and what I would consider decent maintenance. From 104,000 miles to 152,000 miles, my wagon has gotten 13-15mpg consistently in the city and 19-20 on the highway consistently. Runs great with plenty of power.

sherlock9c1 wrote:

The curse about gas mileage is the same as the curse about deals - people only post about great deals or great gas mileage. Everyone else who gets a regular deal or regular gas mileage then feels bad.

I have a '94 RMW with 2.93 posi, stockish wheels/tires, and what I would consider decent maintenance. From 104,000 miles to 152,000 miles, my wagon has gotten 13-15mpg consistently in the city and 19-20 on the highway consistently. Runs great with plenty of power.

I hear ya. That 2006 Grand Prix GXP I just bought my wife, with the 5.3 V8, was supposed to get 18-26mpg. People in the Grand Prix forum posted averages of 22mpg. Well we're getting 14mpg. It's pitiful. It runs great and other than the miles we love the car, but Misty has a 40-mile commute and says for that mileage she'd rather use the Suburban. I'm going to change the fuel filter and get the injectors flushed, and see if that helps.

-Mike

This was the inspiration for my grille. Very pretty car and the OZ's look smok'n hot.

Not a new guy. Been on this forum for many years , just don't post much unless it can be helpful .
Car has been in east central florida near Daytona Beach all of its life.
Thanks for the compliment.
Have a bunch of pictures at https://s151.photobucket.com/albums/s145/etsfl/1996%20RMW/[/quote]

i have to say that roadie is WOW its awsome, cant wait to see it in person , looks so much like my DCM that my girlfriend now wants me to have my new one painted dcm , id never do it, id sooner get another one that color

uxwbill wrote:

Gasoline pumps around here claim that up to 10% ethanol may be added to the product. I don't know if it actually is or not. I'd guess that it is.

On this side of the border, they are required to average 5% ethanol overall in gasoline sold for automotive use. In general, they add 10% to regular, 0% to premium and blend the two at the pump when dispensing "mid-grade".

If more people are buying regular than premium, the average ethanol content will shift upwards, above 5%. So depending on the current cost and availability of ethanol, they could reduce the concentration in the regular grade but still maintain the overall average. Or they may fill a station's holding tanks with ethanol-free gas from a part-load headed for a marina or air strip for the sake of efficient delivery. Really, a more accurate way of labeling the pump would be "May not contain the full 10% dose of ethanol".

buickwagon wrote:

Really, a more accurate way of labeling the pump would be "May not contain the full 10% dose of ethanol".

It's even worse than that, and much worse if you are running E85. Read this.

Hey UXWBill, I looked at your vids last night. Good info on the 3rd brake light fix. I've read that on some cars if the 3rd brake is INOP, the cruise control won't work. I gotta have my cruise control! Ha!

On my Roady I had a really bad rattle from the back. I checked the spare tire well, under the 3rd seat, moved stuff around in the storage compartment, and even pulled the trim off the tailgate door and checked for loose parts in there. Well it turned out that cover on the bottom of the 3rd brake light was loose. Tightened the two torx screws...fixed.

I was SO mad. Ha!

-Mike

I'm getting 20-22 with mixed driving in my 92 OCC, but 70% is Hwy driving. I changed the air filter and fuel filter, ran a cleaner through the fuel system before I even checked MPG.........wish I checked before to see if it improved any, but I'm guessing it probably did.

200OZ wrote:

I get a combined 16.5-17 mpg pretty consistently on my 226,000 mile, 1994, 2.93 rear, BRMW mostly going to and from work, 17.5 miles each way.

Mike

This is about what I get on mu 1991. When I can't keep my foot out of it it drops much, MUCH lower - 15's or so.

Mark, I have a 94 with an ODBI yours being a 96 is ODBII. I use Datamaster on my laptop (not sure if it works on ODBII) and I can see my fuel matrix. When I bought the car I did a total tune up (replaced vac lines, sensors, plugs, opti, etc etc etc. and never got better than 20.5 hwy, but datamaster said all my fuel matrix was rich in every quadrant. Never figured it out. but now the car has 217+K (had 135K when I got it 5 years ago) and I'm besting about 18-19 straight hwy. I attribute it to the increase in ethanol in the gas as ALL my cars get shittier MPG now. I noticed in South Carolina I got 3 mpg better in same driving conditions (less ethanol??) I dunno.

12 mpg on the other hand was what I was getting when the opti was shorting out and firing on 7 cyl. (why I did all the R&R).

@NIck D. When I threw a K&N setup on my stock tune, my MPG dropped 2.5 MPG and everyone told me I was smokin' crack...I drove from FL to NC (850 miles each way) drove up on the K&N got around 18, swapped back to the stock setup in NC and got 20.5 on the way home and most of that is sea level flat driving. (pre corn gas days)

Well,If I may chime in here for a minute.About a month ago we went on a trip from
S.jersey to central Maine. My 96 Roady was somewhat loaded with tools and supplies,
I figure around 850 lb pay load. Using hi-test fuel (10% ethanol) we got about 22.5mpg,
it was all highway driving using cruise a fair amount. My wagon had a fresh tune and also
has a hi flow exhaust system and the pcm has been tuned for mild performance.
I know this sound like a carbon copy of what most of the guys are getting,but just had to
share. ed

Roadagon wrote:

Using hi-test fuel (10% ethanol) we got about 22.5mpg,
it was all highway driving using cruise a fair amount.

Which highlights another couple of variables: speed and throttle control. Higher speeds consume more fuel. IIRC, the US national speed limit of 55 resulted from the Arab oil embargo because above that speed the fuel consumption of the average car (of the day -- mid-70's) climbed exponentially. So someone who cruises at 60mph will likely get better mileage than someone who cruises at 75mph (all else being equal) even though they are both on the highway.

The cruise control is not the most fuel efficient method of throttle control -- but it's better than most drivers can achieve without close and constant attention to detail.

Most of my driving is highway, and I usually set the cruise to about 65 - 70 mph (the speed limit here is 63 mph but the cops are cruising along at 75) . I average around 22 - 23 mpUSg in that scenario.

This past weekend I did some traveling in my Fleetwood. I filled up in Stoughton MA. Drove to Providence, RI and drove around the city. Drove from there to Cape Cod and back and forth to work for a day. The next day I drove to NH for the b-body round up. After that, I made my way to Plymouth, MA where the fuel light came on again. A total of 400 miles on that tank at about 20 MPG. This is assuming I had 20 gal in the tank because I pumped til it stopped and then went a little more to get exact change back. I drove until the light came on, like before I filled up. There should be about 3 gallons left in the tank at that point. Mixed aggressive city and conservative hwy, mostly hwy at about 65mph +/-. The car is slammed on Sprint springs with 225/60r17 tires.