Egr

how do you know when egr valve is going out

Engine may idle erratically

Missing at idle or lacking power

Other faulty components may also contribute to the same or similar symptoms.

All of the above, plus it should throw a check engine light if so equipped.

what happened is, the car cut out at a stop sign, then i restarted it and when i pulled it over, the engine started racing hard when it was idleing; i had the air flow sensor replaced and the racing seemed to stop but it still idles fast when you first drive it. and i don’t have very mush power like it usually does…i replaced the egr 5 years ago, and it was a parts house part and not a dealer part, do you think it is egr more than oxygen or tps; it had a code but it was erased

An EGR valve can fail in two modes. One is where it’s stuck open causing the engine to stall at idle. The other is when it’s stuck closed. This can cause the engine ping when under a load.

Tester

For a better idea of what system the car has, the year of the vehicle matters. A 1977 car is a lot different than a 2007 car.

You think in terms of parts, don’t you? Have you thought about idle control valve, or brake booster vacuum leak?

Model year of your Oldsmobile Delta 88?

it’s a '94 delta 88, i took it to a mechanic 2 days ago and he said he found no vacuum leaks, and he said, to him, it runs fine–but i know my car, and it is sluggish and when i first start it, it still kind of races, and even down my hill at the stoplight, it still seemed like it was racing, then it stopped, but it doesent keep it’s power when you drive a stretch, like it drops off and does this chugging and i have to excelerate to keep the momentum going, very noticible to me because this car drove incredibly before this happened. 3 weeks before i had the manifold gasket replaced but it ran fine after that. they said the plugs didn’t sound like they were bad. i know i have never replaced idle valve. i hang on to this car because it has been amazing, but when it comes to sensors, i get crazy. the mechanic said that unless there’s engione light on, he doesn’t know what to look for, what do you think?