I finally sprung for a new IAC valve and wow, it idles perfect in park. My problem now is that in any other gear like D, or R the engine almost dies. When I brake quickly or take a tight turn from a stopped position it either comes extremely close to dieing or it just stops. I replaced my MAF a few months ago, and a shop redid all my vacum lines, or atleast it looks that way. The car looks great now and Ill have some pictures soon now thats its painted, but I hate it when someone looks at my car with envy, then smirks when it stalls out.

 

How's your idle speed? What rpms in neutral? How about when you put it in gear? Kinda strange...the symptoms still sound like an IAC valve.... But assuming it's not defective..lol....try getting your hands on a vacuum gauge if you can and see how much vacuum you're pulling at idle. Also do a visual check for leaks, cracked hoses, and unconnected/missing hoses. When I first got my other car, I only checked the hoses, which were ok...but after having an odd and sometimes EXTEMELY lopey idle (like it had a cam!), I noticed a fitting on the back of my manifold. The car was missing a vacuum line going from the manifold to the Fuel Pressure Regulator...I plugged it temporarily and it cleared right up.

Also, if you're capable, check the TPS reading with the engine off. Check it with the throttle closed, and then slowly open the throttle all the way open and see how the reading changes.

Finally, check your fuel pressure. I'm thinking you MIGHT have a bad fuel filter, as far a stretch as that sounds to me. You can get a fuel pressure tester kit, if you don't have one, at Autozone for like $25 I believe....you can attach it to your Schrader valve...it's off of one of the fuel lines and kinda looks like a tirestem.

Hope any of this helps.