rough idle
 

my 88 TPI car idles very rough and usually stalls when in park or neutral, idles fine in drive. checked the fuel pressure and its good, cleaned the hell out of the IAC, i dont wanna spend $65 on a new IAC if thats not the problem, anyway to know if its working? what does it consist of inside? i cleaned out the whole throttle body also

i had the same problem and got a new IAC and it didnt help so dont jump to buy it...

http://info.rockauto.com/Airtex/2H1037.jpg

that is what one looks like for your car though

edit:

btw rockauto.com has it for $35

Start by Checking for vacuum leaks. Look for any cracked lines and replace them. Make sure you got good spark plugs and none of them are fowled and check your plug wires and cap and rotor. If all that checks out good and still have a problem then you may have to start checking your sensors for problems.

what he said, vac leaks, stuff like that...to test your IAC just unplug it and see what happens, but it shouldnt idle at all if its a bad IAC.

what IS IAC btw?

intake .....something something?

i beleive its Idle Air Control. i could be wrong. it sounded right in my head tho.

What I find odd here is that you're only having the problem in Park and Neutral.....usually with a bad IAC or TPS you'd see the problem show up in gear when there's a load on the engine. I would try to get a scanner on it or at the least check your TPS voltage and possibly try cleaning the burnoff wire for your MAF.