Hello!

I have a problem with my car, and I was wondering if you all could help me diagnosis it. My car is a Chevy Cavalier Convertible, 1996, with the 2.2 liter engine.

Back in February, I had a leaky fuel injector on cylinder one, as evidenced by the fuel on top of the fuel injector. I replaced it with a new GP Sorenson injector from AAP. When pushing the injector into the manifold / fuel rail (they are one piece on my car), I used Vicks VapoRub to lubricate where the injector fits in. (I didn't have any vasoline or assembly lube). I got it in, put everything back, but I forgot one thing... I forgot to plug in the electrical connector to the new injector. I started the car, misfiring on cylinder one, and ran it like that for about two minutes. I turned it off, and figured out what I did. I plugged in the injector connector, started it up, and it ran fine.

A few days later, I recognized that the engine idle was a bit unstable. I also got a P0300 (random multiple cylinder misfire) code. The MIL was on for three trips, and then turned off. Since then, the P0300 has thrown a few times (when the idle misfiring is especially bad), and then turns off after three trips. The engine takes longer than normal to start when the engine is cold, and the idle is particularly rough. If I pump a little gas in it, it seems to smooth out to mild unstableness. It starts up immediately when the engine is hot.

I have replaced the PCV valve and hose, air filter, cleaned out the air intake plenum with carburetor cleaner, cleaned the IAC valve, cleaned out the MAP sensor, checked the resistance on the ECT sensor (it read fine), checked the resistance on the IAT sensor (it read fine), looked at the spark plugs (all of them looked normal, except cylinder one was a little blacker than the others), and run a bottle of STP fuel injector cleaner in it. The catalytic converter is pretty new (about two years), and I replaced the after-cat oxygen sensor nine months ago.

Any help on this would be appreciated!

Joshua

Sounds to me you may need to do a compression test done could have a bad valve in the cyl head or intake gasket leak. I would also check the ohm reading on the coil packs as well. Also wouldn't hurt getting, youre fuel pump pressure test done as well.

Good Luck.

Hello again!

After replacing the spark plug wires to no avail, I decided to replace the new GP Sorenson injector with a junkyard one. Doing so fixed the rough idling. I'm returning the GP Sorenson for a refund of $70! Sweet!

The end.