Pontiac Repair: Engine issues?, vacuum leak, engine temp

Question
Hi. I own a 1999 pontiac grand am standard edition. It's an automatic. 2.4L 4 cyl engine.
Hi. Ever since winter came along, I noticed that the car would idle very roughly when it was in drive at a stop, but was resolved if I shifted it into park. The whole car seemed to shake, and since then the "check engine" and "track off" engine lghts have been lit. It seems to idle the most roughly in cold weather, and when the engine itself warms up there is no effect. Gasing the car slightly while stopped seems to resolve the problem for the mos part.

And I began to notice other issues too. When my car starts cold, it idles itself way up...almost 1800 rpm until the engine temp is high enough (120 degrees?). It does this in park also. Sometimes i have to ride the brake until I can hit the highway to keep it under control. When idleing normally (as rare as that is now) it sounds like the engine revs up a little...then down..and back up again in cycles. Also..pertaining to the transmissin..when I'm going between 20-45 mph and I let off the gas, it feels like it's trying to downshift but it's like it can't find the gear and it shifts around frequently. And after long trips the engine performance degrades rapidly...slow accellerations at redlights..a burning smell (even though oil and temp are fine) and stuff like that. Speakng of oil..it uses oil really fast but it's not leaking out.

I'm lost on where to start...what could this be (or at least related to)
thanks.

Answer
Hey Billy:
I would start by looking for a Vacuum leak. Possinbly the hose from the manifold to the MAP sensor. The throttle plate and throttle body should be cleaned out they have a tendency to carbon up and cause all kinds of issues. I would also take the idle control motor out and clean that up as well. The trac off light can be on in conjuction with a sevice engine soon or service vehicle soon which one is it? The trac off light will come on with an ABS lamp and it will come on with a Check engine light both. stop by one of the big box auto parts stores they will scan your car for codes for free see what codes are stored in which modules and then you will have a place to start looking. untill you know what codes are stored it's useless to even guess.
As far a the burning smell it could be coolant these engines were noted for water pumps leaking.