Diagnosis problems ? Or bad mechanics

I have a Chevy Cavalier 1996. When in Idle makes a puff, puff, and shakes and quit. I took it to more than one mechanic, one change the wholw exhaust system ande oxigen sensors, one, put a new ignition coil, another one a new egr, last one, change the spark plug wires and the spark plugs as well as clean the oil water separator, but, the car still is doing the same thing. Anybody have any sugestion of what can be wrong in it?

Try this. When visiting your NEXT mechanic, ask him if he can fix the car. If he says yes, say fine, but I’m not going to pay you unless you do…Can you STILL fix it??

By the way, how many miles on this Cavalier?

Has anyone done a compression test? It sounds like there is one cylinder with low compression.

I’d also like to know more about the oil/water separator, never heard of that on a Cavalier.

Has anyone put a scanner on it yet??? Checked for codes???


Good idea, thank, I appreaciate it. 120,000. Miles.

A puff puff or backfire through the intake can be a fuel supply problem. No codes will show up for this but you would want to verify the fuel pressure when it does this. Could be an intermittant pump problem, pressure regulator, idle air control, etc.

It’s really not a good idea to constantly shuffle from one tech to another because that leads to a constant “who done what” and just makes any problem worse.
Maybe it was justified in this case but not enough info is known about the who done what thing.

You said the last one replaced the plugs and wires. Well, if that was the original plugs and wires that were changed then it’s entirely possible your car needed all of those other things because they’re all affected by the lowly spark plugs.

Wild guessing a bit, I would lean toward the problem being a vacuum leak or an Idle Air Control Valve problem. The IAC is a vacuum leak also but it’s a controlled one; at least if it’s working right.

In the meantime, you might have AutoZone, Checkers, or whomever scan the car for codes and post back. They will do this for you free.
If no codes are present then I would be leaning even more towards an IAC or vacuum leak problem. It’s entirely possible to have an IAC hiccup with no codes set.

They scan It in Auto Zone and no problem was found, but, I am 100% percent agree, it was a big mistake jumping from tech to tech.

About the IAC, and a vaccum leak, I am agree also, I am going to check myself both and wherever I find out I will let you know.