Engine Performance problem
1998 Chevy Cavalier 4 cyl Two Wheel Drive Automatic 40000 miles
I bought this 1998 Cavalier in 2006 with just over 12,000 miles on it. After having it for a year around inspection time the car was acting up, as my mechanic fiance said, it was " rough idling". I would be stopped at a light and the car would try moving forward, the RPM's would just from 500 to 1500. Finally after about 15 minutes of that the light came on. At the time my Fiance worked at Pep Boys, so he took it in for the new tires, inspection and correct the Check Engine/Idle issue. The Master Tech there told me it was the EGR Valve, so I spent the money to have it replaced. All cleared and checked out ok. A month later the car did the exact same thing. So I had the warranty the EGR and replace it. My Fiance still has the part that was pulled out of the vehicle, and he says it looks perfectly fine. Which he kept the part just in case. That seemed to work, every so often the RPM's would jump for 500 to 1000 nothing as bad as before. Around the inspection in 2008. It did it again. This time worse than before, I felt as if it wasn't getting enough fuel. I had my local mechanic I went to before I met my Fiance take a look at it. He didn't find a need to replace it and cleaned it out. Around the same time my brights went out as well, during that same year, I had to replace my Altenator at 30k miles. Which they thought was unusual. They rewired my headlight issue. Up until February of this year I was doing fine. Around inspection time, my brights went out, then came back out and the passenger side went out. Then the rought idle came back in. But this time it was worse than it ever had been. The car was to the point that if I stopped, or was in the process of stopping the car would stale out. Then it wouldn't do anything until hours later. So I had to constantly drive two footed. So I called my mechanic and consulted with my fiance, and decided that the Fuel Pump needed to be replaced and that was my problem. So we replaced my exhaust system from the Cat. Back. And the Fuel Pump. Car ran beautiful that day, within 24 hours car ran like crap again. So we decided that since the EGR Valve deals with carbons and half the exhaust system was new that we would go ahead and replace the Cat and front pipe. Started it up, did one choppy moment, and then it ran beautiful. A couple days later my check engine light came on, car ran fine. Ran the code it was a Downstream O2 Sensor. So we replaced that. In the last several days, my fan has been constantly running, then the Check Engine light is back on reading the same error message in Regards to the EGR Valve stuck open. We were going to replace the EGR bipass tube, but no GM dealer, has them or can get them. So he cleaned it out. We are running out of options. My vehicle is low miles, and practically fully replaced! Our last options would be a MAP sensor, and a good cleaning out of the BiPass tube again, and cleaning the EGR Gasket. Any ideas!
I had the exact same problem. Code 404, the egr valve that sits above the exhaust manifold. My mechanic told me either to replace the egr valve or let it go, since the CHECK engine light comes and goes periodically. When it is off, everything is fine the car runs great. Then, the engine will start to misfire, followed by the CHECK engine light at the code 404. My mechanic says sometimes pieces of carbon will come off from inside the exhaust manifold causing the EGR to stick. So when it works again, it "fixes itself" by the piece coming free from normal use. The mechanic says when you put fuel injector cleaner inside it sometimes causes junk inside the engine to float away and sometimes it gets stuck inside the EGR causing the code and misfire, plus the CHECK engine light coming on.
For now, I am not replacing the EGR, but I will not be adding any more aftermarket fuel cleaners, as I've heard from more than one person that nowadays they simply are unnecessary, as long as you avoid commodity gasoline (e.G, the kind sold at a large grocery store, like Safeway).
My rule is from my training at mechanics school: Rule #1: If it's not broke, don't fix it.
Sometimes, also the cavalier has a problem with the idle air control valve, a $40 part that is easy to replace so you might want to check that out. The OBD (on-board diagnostics) will give you the trouble code and I would go from there, since you want to repair the right system or part.