I have an old '91 Cavalier VL (4cyl, 2.2L) and we have started having problems with the car.

The Cavalier basically starts fine, runs fine, and has no problem until we come to a stop sign or an traffic lights and have to stop. For short trips like say 30 minutes driving or less, no problem even at a full stop. But if we drive on the interstate for an hour and come to a stop the engine rough idles and dies. On restart it most often dies immediately when put in drive. It sometimes takes four starts before it continues running when placed in drive.

I will also mention that the day we had this problem occur, we noticed that we had been driving for a few days without a gas cap. Our local service station apparently had forgotten to put the cap back on after refilling. After noticing the cap we immediately replaced it.

I want to replace the fuel filter but I cannot find it. Where is the fuel filter for a 1991 Cavalier VL located?

I had a Dodge Spirit that had the same problem. It would start running rough after a period of time. It was always after 45 minutes of driving. No CEL was set. Talked to a Dodge mechanic and he said when in doubt replace the O2 sensor. He said it won't trip the CEL all the time. I changed it(Spirit only has one)and that was the problem. Hope this helps.