My 93 LT1 6 speed coupe runs pretty good but lately after it has been running awhile, when I accelerate from a stop or changing gears it stumbles. The exhaust sounds like a burble and it does not pick up speed. It does not stall just kinda rumbles. I continue to accelerate and it seems to pass. Happens in all gears. If I am cruising in 4 or 5th and accelerate it will stumble but not stall. It does continue to gain speed but slow with the burble, then it seems to pass. Does not do it all the time. It seems to happen after I have been driving for a while (+20min). I am looking for suggestions or idea on what to check before I tear in to it.

One of the first things you can check is fuel pressure. You can get a pressure gauge at pep-boys or autozone and hook it up to your schrader valve. See what your pressure is during idle and throttle. Also, leave it hooked up overnight and see if you have any leakdown. Report back and let us know whta you find. Could be a leaking/faulty injector or fuel pump.

Good Luck

need more info... how many miles and maintenance history.

one thing, the stock AC Delco platinum plugs SUCK.... big time.

They have a platinum puck on the ground strap. Over time (as little as 30k miles) the puck will either fall off or erode away. This takes the gap from .050 to .065... bad... real bad.

And a gap like that will cause problems.

I assume there are no codes?

Quote:

I have just over 52K and for the last year have not had any problems. It sat for about 3 months (Jan - Mar) with a dead battery. Replaced it and and had no real problems other than then the fob won't program. I am gathering a list of things to look at and will start with teh simple and work my way up. Appreciate the response and help.

Something similar happened to mine with the same symptoms.

My tranny went out and I parked it for a few months during the winter months. After I got it all back together, it stumbled and even stalled at stop lights at times. I changed everything out and finally checked to fuel pressure only to find out it was reading approx 20lbs(norm is around 35-42).

I pulled the fuel pump out and noticed rust around pump brackets and such. Replaced the pump and she has been great ever since.

Not sure if this is your problem, but worth a look. Unfortunately, it can be a 100 different things, and you just have to try to narrow it done to the problem without spending money(or too much money).

Good luck!

I'm with Bruthish, it sounds like something has fouled up in the fuel system.

Check the fuel filter, too. If any rust made it's way up the line, it will clog the filter.

And then, the biggie, the fuel could be old and stale.

First I want to say thanks to all who responded. I really appreciate the generosity of the members who are willing to give their advice and expertise so freely. I have been able to do some little things to correct the problem and just want to let you all know where I stand. First I replaced the spark plugs. Now I am not a small person but I am not a giant either (6'2" with what I think are average size hands.) I would like to meet the engineering midget who designed the engine compartment. My hands are cut and scrapped from the tight fit of all the peripheral equipment stuffed into the engine bay. Anyways a better part of a Saturday and they are replaced. I also replaced the left side O2 sensor. I took it out for a drive and pretty much had the same problem. I know I will have to replace the right side sensor but it was running late and I buttoned it up for the day. I put a bottle of Techron in the tank too. I will replace the rt. sensor and the fuel filter on my next free Saturday. The spark plug wires looked pretty good, not cracked or stiff. If that does not fix the problem I will be back looking or more free advice. Again thanks to all.

Hey no problem!!! Welcome back! We do hope you come back for more!

the wires could be carbon traced... once plugs go bad, the rest of the system gets all icky because of it.

I would not be surprised if the cap/rotor are burned up.

[size=12:60df1005a8][font=Comic Sans MS:60df1005a8]Well I put her up on jacks this past Friday to change out the right O2 sensor and fuel filter. It was apparent after trying to get my hamhocks in the area that there is no way I was going to be able to get tools, hands, and and apply any leveage to those parts. I applaud anyone who can do that job on their back. Looks Like I am going to have to go for a more professional approach ($$) and have a shop with a lift take a stab at it. [/font:60df1005a8][/size:60df1005a8]

go to autozone and rent the O2 tool kit.

It has a special offset socket (clawfoot) that will reach the O2 from the top with a long assed extention and a ratchet.

Is it sorted yet? You say it only starts to do this after it warms up? The new O2s havent fixed it? Check for faulty injector/s and also check the ignition control module. Knock sensors working? (long shot that last one)

It has been awhile since I posted an update. I appreciate everyone who provided advice. Here is the latest.

It still (My 93 LT1) starts up fine. Runs rough, Sputters a little when cold and then when it warms up it gets rougher. Occasionally it will backfire. Not bad but noticeable. The backfire appears to be only on the right bank. I changed spark plugs (Cheap Bosh ones) and replaced the O2 sensor (Bosh). It does not throw any codes.

Had some experienced mechs at my place of business check out the fuel injectors and they were fine. The mechs seem to think based on the rough idle and a smell of fuel that it was the Opti going bad. My question is this...Would an Opti going bad only affect the right side?

Your 93 has 2 O2 sensors. One for each manifold, right in front of the cats.

Have you changed plug wires in a while. Inspect them for burn marks.

Yes, an opti could only screw up one side but that is unlikely.