Stumble-Hesitation '94 RMW LT1 that I Just Bot And Returned To Seller...

This post is an offshoot of another forum where I was flying to Florida to buy a '94 RMW.

Anyhow, I got a bunch of repairs done, and when I drove way from the sellers house I immediately notice a stumble upon acceleration and cruise. It's random and in the 15 minutes I drove the car I didn't notice any pattern, just a buck here, and stumble there. I was so PO'd that just after I filled the tank, I turned around and drove the car back to the sellers house and left it there. He wasn't home, but we spoke the next day and we're not in greement of what to do.

But a friend who watches my videos has expressed interest to buy the car if I can repair it and get it home. The seller says he changed the OptiSpark and water pump some time back.  To me it feels like a lack of spark. I suppose it could be anything. It has good power so I doubt it's a blocked fuel filter. It idles smoothly.

I did flush the cooling system, so water may have gotten on a couple of ignition wires, but I let it idle for 10-15 minutes till it ran out of fuel. I put in 3 gallons and the rough idle immediately cleared up. I then let it idle again till it was hot in order to drain the oil (hot). I subsequently drove it to the gas station a mile or so away, and that's when I noticed the stumble. As I mentioned up top, I drove it a couple more miles till I decided to turn around and it was bucking somewhat on that drive at a steady 45-50mph cruise. I don't think it's the TC lockup.

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I wish I knew what was wrong with the ignition causing the stumble

You also likely hurt the fuel pump by letting it run so low on fuel, so that could soon be expensive to repair.

Take it to your mechanic of choice and let them diagnose it.
The seller isn't really liable for anything as they didn't warranty anything.

It sucks, but its part of buying used cars.

Replacing the fuel pump isn't very hard to do. It's just a pain in the neck as you will need to drop the tank. Close to empty is best but it never turns out that way.

sswagon wrote:

Replacing the fuel pump isn't very hard to do. It's just a pain in the neck as you will need to drop the tank. Close to empty is best but it never turns out that way.

My 96 was expensive because it was all rusted to crap and they had to replace the sending unit or something else because of the rusted lines.

Can I see some more info on the OS? Where should I buy parts from RockAuto? Plugs?

I went to look, $100-$300 for re-man AC Delco

Tell me more!

I just remembered, there was a ground strap dangling by the LR wheel. I meant to re-attach it. I know ground straps are vital. Hard to say if this was the cause of any of the probs. Could be any number of others not connected or broken too?!?!?

I suppose I'll find out what is so bad with the overseas OS's, but we're on vacation and about to hit the road to switch rental cars and drive across Florida-Alligator Alley and Mrs wants to hit the road as we're getting a late start this AM.

Briefly, could a Cheapo OS cause a stumble? It idles smooth and has good power, just bucks-hesitates alot. I accelerated strongly on the brief drive I took and she pulls strong, just the nasty hesitation is always there... Like the power is being cut for split second. And it's random. What is required to "plug it in?" A friend said he uses a laptop as code scanners don't work with OBD 1.5

call me, I sent you a PM with my number

Shall do!

Could the EGR Valve be the culprit for the hesitation issue at higher speeds?

No, I highly doubt it's the EGR. I spoke with sprocket, and we think it's the dist cap and rotor and or the plate under it may be burned thru. Could be a bad wire or two as well, and they're difficult to change. PO says the OS was changed, and plenty of miles have been put on since, and I doubt a GM OS was used.

I would need a pix of the little nuisance screws that hold the cap on. Sprocket says the screws have a stupid small torx or similar head.

So I'm 500 miles away now in Sanibel Island, and thinking to just have it shipped north, and I'll deal with it at home. I can't drive an unreliable beast w Mrs breathing down my neck.

As I mentioned earlier, I have a friend closer to home that wants it, but he has no mechanical skills. I can more easily fix it at home, and to fly 2 folks back to Florida, hotels, fuel etc I could ship it for the same cost, and my summer is mostly planned out, so don't have the time to play

There is a Florida based shipper that another Florida based member recommends, Affordable Auto Transportation, [You must be registered and logged in to see this link.] Try them.