More Malibu Troubles

You would think with a name like malibu that owning one would be like having a small piece of paradise right? Guess paradise has it's troubles too, I just recently replaced my coil cover on a 98 Malibu 2.4L and I'm getting ready to replace the catalytic converter. The car was operating on 3 cylinders for about 300 miles before anyone fixed it. The cat was getting red hot and my car is stuttering pretty bad now even though it's running on all 4 now. It mostly stutters trying to get out of 3rd going into 4th (automatic) and when I really get on it. Are there any known issues that I should know about before replacing the cat or anything that would be a good idea to do while I'm going to be in down time?

Also I've noticed that the stuttering progressively gets worse as my gas gets lower. Would that problem be something related to the exaust or the fuel system? I'm thinking a new fuel filter and some injector cleaner would do me some good.

I would think that a new catalytic converter would certainly solve some of your troubles. Sounds like it could be REALLY clogged since it's turning red.

It was, but it isn't anymore (not since I changed the coil cover). But like I said, the car was operated for awhile before the cover was replaced (I bought it like that). Anyway I'll post when the cat has been changed.

Replaced the catalytic convert yesterday. My car is running a lot smoother but it's still missing occasionally during idle and the car stumbles during hard acceleration or while accelerating uphill.

Pull codes..

Tune-up! When's the last time you changed plugs, wires, check coil packs, fuel/air filters? check pcv valve.. and check for vac leaks.

Check fuel pressure.. I think it should be 40 some psi.

Clean/replace injectors.

How about compression test on all cylinders..

-Mark T.

No code. Replaced coil cover and plugs just under 2 months ago, replaced the air filter a month ago, I've been running only 91 octane gas since I got the car and I just ran fuel injector cleaner in the last tank. I'll check the PCV valve, vac hoses and fuel pressure tomorrow if I can get a proper connection to use with my tester. I'll save the compression test for last.

Oops..

The I4 doesn't have pcv.

-Mark T.