Hello everyone, I recently acquired a 1997 2.2l cavalier as a work commuter to save on gas. Unfortunately a week after the purchase I'm already having issues!

Today suddenly, it began sounding as if its running on 3 cylinders, yet all four are firing. (I checked by removing and replacing all plug wires 1 at a time) However, when I disconnect the spark plug on cylinder 4, the engine goes back to what I consider to be normal and smooth. Plug it back in and the problem returns. All cylinders have been checked for compression, and they all looked good. No coolant in oil. Removed the valve cover and ran the engine, all the valves appeared to be lifting/moving properly. There are no abnormal signs of oil around the head gasket area, or pooling under the car. The spark plugs were not wet at all, although some minor carbon build up (definitely could use a tune-up).

The problem did not creep up on me slowly, I drove it 400+ miles over the weekend and was great. Left the parking lot at work today and it suddenly had very little power and began running very rough. Could not accelerate over 20mph quickly at all.

I feel that I can safely rule out head gasket issues, lack of spark at the plugs, lack of fuel... One additional tidbit is there is a check engine light, and the only code was a P0141 O2 sensor, bank 1 sensor 2. Yet it was running just fine with this light and code on (had it cleared previously) before this problem arose.

Any help would be greatly appreciated! My friend and I are rackin our brains to no avail... Any ideas will be appreciated as I really would like to have this thing running well to save on gas...

Is the cat bad? Maybe your coil pack went or you have a bad fuel injector. You could try switching the coil packs around or testing them. See if the problem changes.




On the inside my car looks like a fighter jet.

Thanks for the input Rob, those are good suggestions. Forgive my ignorance, but I've only been working on cars for a short period of time, but are you saying these cars have multiple coil packs? Where are those located? How would you go about testing a coil pack? Also, what would be the best way to check if the cat is bad?

This may help everyone understand my problem better, it's a video of me running the engine with the problem, removing the plug wire from cylinder 4 where it smooths out, replacing the wire and it goes rough again - http://www.youtube.com/watch?v=T126gHcZWv8

Here's a list of things I plan to do to try and pinpoint the problem. The goal would be to do the free/cheap things first:

-Try running the engine on only 1 cylinder at a time to verify all cylinders are firing
-Remove/disconnect O2 sensor 1 and try to run (on exhaust manifold)
-Remove/disconnect O2 sensor 2 and try to run (after cat)
-Check for bad cat converter (remove????)
-Re-gap/clean plugs
-Replace plug wires
-Switch coil packs???
-Check/clean fuel injectors
-Check O2 heater fuse

And here's a list of things I've already done:

-Checked compression, all good
-Topped off oil
-Checked coolant level/color
-Checked plugs for wet oil residue, none found (plug gaps are HUGE!! need re-gapped...)
-Ran engine then removed and replaced each plug wire (went smooth when #4 wire pulled)
-Checked each plug for spark, all sparking
-Removed valve cover and ran engine; all valves seem to be moving correctly
-Checked for any signs of head gasket leak, none found

Keep the ideas coming! Need all the help I can get...

I had a very similar problem on my Sunfire. It turns out that the rubber tube on my MAP sensor was worn out. After it was replaced, it works much better.