1994 Pontiac Sunbird - Please Help

Can someone please help me? I have a 1994 Pontiac Sunbird with a 3.1L V-6 engine. I purchased this car a couple of months ago and it just won't idle right. The RPM's may shoot up to 2 thousand when you start it and then go down till it almost stalls. When you come to a stop it will keep going up and down on the RPM's. Sometimes it may idle perfectly, but 90% of the time it is all over the place.

I have installed new spark plugs, new gas filter, new exhaust, and a new O2 sensor. What should I try next? My budget won't allow me to try all kinds of new parts in a trial and error method. So can someone please tell me the most likely fix, and if possible the approxament price of repair.

Thanks to all in advance for helping me!!

Clean two items, the idle air control motor located on the throttle body and the mass air flow sensor located in front of the throttle body. Use carb and throttle body cleaner on the IAC motor and use electronics cleaner on the MAF sensor. Spray the IAC until it is clean and reinstall just don't move it in an out while you have it off. Secondly, spray the MAF gently with electronics cleaner allow to dry and reinstall. This should cure your problems.

Is this a hard process to do? Can I screw it up in any way?

i have the same problem, i took the advice but i have no idea where those senseors are exactly.. i know i took off 2 senseors the only ones connected to the throttle bodie but i dont think they were the right ones. i cleaned one that had a spring in it .... when i put it all back on i left off a a gasquet,from something hooked up to the back of the throttle body, that basicly crumbled when taking it all apart i think that threw off the vacume cause it sounds like air is comming from it and the engine is now idleing all over the place , way worse than before. im making a new gasquet tomorrow and ill leave another post to let you know what happened

just to let you know when i put the new gasket on it ran somewhat better but im pretty sure what i cleaned wasnt the MAF sensor because it wasnt and electrical part so maybe when i find that and clean it my car will run better

i change my opinion on that the rpms jump around more often now but the rpms are under control more at driving speeds than before

Try cleaning the two sensors as GTP DAD said and also clean the throttle plate.