1992 Lurches

My 1992 Caprice wagon 350 TBI lurches, 200k+. Doesn't do it all the time. Usually feel it when going 60-70 up a slight grade. Seems like the engine power is lost for a millisecond or the tranny or diff slips. The vehicle lurches and then returns to normal.

Twice in the last week it was more severe, where it cut out for a longer time, maybe 1/4 of a second, twice within 5 seconds and then kicked pretty hard.

Some days it never occurs, I drove 600 miles last weekend and felt it about 8 times always going up a grade.

Been lurking for a while, and thought I'd ask the experts.

Any advise on what or where to look is appreciated. Hoping it's more fuel or engine related and not trans or diff.

How long since its had an ignition tune up? Fuel filter etc?
plugs wires cap rotor etc,.

with the converter locked,. rpm down (remember these wagons have Looooong gears in them)
pulling up a hill, thats when the plugs will break down,.

Internet diagnosing is never an exact science,..

I agree with Phantom309. Tune-up if not performed w/in last 40k is a good place to start. Original trans? Any recent engine work performed... top end, head gaskets, manifold gaskets, valve train, etc.?

I had issues with the car cutting out/misfiring. Got bad enough for me to check the under the cap, distributor was totally trashed, and I have half the miles you do. New distributor and GM module, runs like a dream now.

You may want to start by checking everything suggested, and check the base timing. Mine was 4 degrees off and was a bit rough when changing gears, etc. Now runs smooth since I got the timing on factory spec.

Thanks for all the input.

It been a long time since my last tune-up.  Probably 3 years and 50k+ miles. (almost feels like confession)  

Haven't have done a fuel filter either.  Maybe I should do that huh.  

The only work I've done recently is fix the exhaust at the cat / tail pipe, had to install a 2 piece clamp to replace the rusted out factory bracket.

The motor and trans were exchanged from my 93 that was totaled, they have not been rebuilt.

prob plugs as mentioned...ur gas mileage will get better too.

When replacing the cap and rotor, make sure you get the rotor on completely. The shaft usually gets rusty, and you may have to clean it up a bit before installing the new rotor. I tap mine on with a ring of plastic pipe, and a heavy hammer...it only requires a light tap. You are also pushing the ignition wire life. Make sure nothing touches anywhere. The kits for ignition wires always have one wire that is way too long, and one that you can pluck like a guitar string when it is installed.

The module in the distributor should be OK, just check the screws for rust. Do not lift the module, or you need some of the white hat sink paste from Radio Shack. If you decide to remove the module, and the clip breaks, you can swap it with the plastic clip from a cheap coil. The "pins" have a tang on them, and you can push them out with the wire after depressing the pins. The module screws are nearly impossible to get, so be careful with them.

And go for a fuel filter. With the quality of the petrol nowadays...
Pete

Bad Ignition Modules will indeed cut out an engine. Because of their location , back of engine, under long cowl, they are known for heat related failure. If you have over 200K on the original, I would not hesitate to change it. As Fred said, you need heat conducting paste, not electrical conducting paste. DON"T use the stuff that's made for spark plug boots.

As long as you are in that far, I agree spend some money on replacing the cap, rotor, plug wires and plugs as well. It's cheap insurance.

Dave

Fred Kiehl wrote:

The module in the distributor should be OK.

I disagree. Both my wagon, and my brothers sedan needed new ICM's after a full tune up when leaving the ICM alone. Both exhibited the same symptoms and were fixed once a new ICM was installed. When it went on the wagon, it caused sluggish performance, rough idle, CEL, stalls, etc. For an extra $35 for the delco ICM, it's piece of mind especially if it's the original to the car.

Been working and playing. Had a little time before the Holiday weekend, installed new plug wires, cap & rotor. Still have new plugs waiting to install.

The 3 things that were changed did fix the lurching issue.

Towed the pop-up to Lake Michigan to do a little R&R over the holiday. The wagon got 15mpg towing over 2000lbs, the back was loaded and the family (4) rode in comfort.

I'd been averaging about 16mpg with mostly in town driving before always heavily loaded.

Thanks for all the input.

I'm sure we are all glad to be of some help either individually or collectively.

Dave