Fuel Problem Or What....My getty up won't go!

[billroth]

I have a 88 with 71k on it and here is what happens. After the car warms up I experience: I step on the gas it stalls and I hear a couple of muffled backfires. I let up on the gas and it remains running. Hit the gas hard, transmission down shifts and nothing. Once I got it at highway speeds and it was fine for 80 miles.

To date I have had the car at a Chevy dealer for about 2 weeks and $1000+ later I still have the problem. They have replaced the Mass Air Flow Sensor, computer, fuel filter, EGR valve, fuel pump pressure is good and replaced several electrical connectors. They get several different codes, but I never get a "service light".

I like the mechanic, but I don't want to pay for his next Vet. Any ideas that I can pass on to him.

Interesting side light, while they were checking Tech bulletins they noticed there were four recalls on the car, which they are taking care of at no charge!
Bill

 

[Crucifix]

Hi,
I have a similar problem with my '92 except for the backfires and only when I am at a dead stop. I have posted today asking for help.

Peter

 

[Jeb]

Did they check the cats for back pressure?

 

[Moonunit 451]

Did they check the cats for back pressure?

That's what I was thinking as well.

 

[Ken]

I'll throw in with this suggestion.

Did they check the cats for back pressure?

 

[tyrel]

Sounds like your mechanic is just throwing parts at the problem. The parts he replaced were probably still in perfect working condition. For much less than $1,000 you could have bought the service manual on Ebay and loaned it to your mechanic so that he can diagnose the problem instead of throwing parts at the car. With your symptoms I would suspect the timing, the injectors, the fuel pump, the fuel pressure regulator, the computer, even a worn serpentine belt can cause all sorts of problems, but the thing is that there are ways to test all of these things without having to replace any of them. It's incredibly easy to test the fuel pressure, for example, or to test fuel flow rate. A simple vacuum pump and gauge could have diagnosed your EGR valve without your mechanic going through the time and expense of removing your plenum. How many hours did he charge you for that?

If your mechanic doesn't know how to diagnose a car, I suggest you find a new mechanic.

 

[WhalePirot]

I'm with Ty on this one, but if your revs are limited, the CAT could be bad. It, too, can be tested, and that thread is herein.

At least you got the campaign stuff done.

 

[billroth]

Thank you for the confirmation, but my problem is what is the 'cats'?

 

[DRTH VTR]

Thank you for the confirmation, but my problem is what is the 'cats'?

Catalytic converters. They provide a catalytic surface that exhaust gasses pass over, combusting unburned fuel, and converting sulfur and nitrogen compounds to a less harmful form. They degrade over time and can present an obstruction to exhaust flow.

 

[Moonunit 451]

In the middle of the car, pass side, after the Y pipe before the muffs. There are also two smaller ones, one on each side of the Y

 

[RichNJshore]

I had an old camaro when I was a kid and the element in the cat came loose and basically clogged the exhaust leading to bachfires loss of power rough running and stalls

 

[davec0_17]

I agree with tyrel, $1000 and the car is still not fixed, your way past due for a new mechanic. I would have guess fuel pump, if its electric. They have been know to heat up and fail. But no need to guess, there are ways of testing these things. Good luck in your search.