Ive got a '98 Cav with the 2200. About 2.5yrs ago it started running pretty rough and extremely rich. It would puff out black smoke and coat the back bumper with wet black speckles. I replaced the O2 sensor, coils, spark plugs, coolant temp sensor, and EGR to no avail. I stopped driving the car about the same time when I got my 240sx. I just recently started to work on the car again in order to get it running so that I could sell it.
I charged the battery and drove the car for like 35 mins to a place where I can store it and work on it, during the 35 min drive it used over a 1/4 tank of gas. I noticed that between certain RPM's it wont run quite so rough, however it never runs completely smooth.

Does anybody have any ideas as to what it may be? Im at a loss right now, and I need to have the car gone soon. I really dont want to strip it and send it to a junk yard. Thanks

Forgot to mention, I also changed the ECU.

To give an idea of how it runs, imagine a WRX with an exhaust at idle

How about youre fuel filter / air filter / Could need O rings replaced or fuel injector gone bad. Cat Convert is plugged?. Possible Vaccum leak, Hose cracked.

GoodLuck.

it's gotta be throwing codes. those would help.



87 Firebird
All stock...........lol.

Improper gapping, spark jumping through plug wires due to bad or defective insulators, could be defective coil or even an airway blockage. Or, you have my luck...


My wife's 2003 Ecotec 2.2 liter Sunfire:
* 2 1/4 inch in and dual 2 inch out muffler Trans Am muffler
* 2 1/4 piping to a very long 2 1/4 inch resonator
* 2 1/4 inch catalytic converter
* an AEM true cold air intake NOPI edition
* 8 gauge ground wire kit
* Toyz front strut brace
* Russell stainless steel brake lines all around.

fuel pressure regulator, leaking injectors