finally went and got a new iac valve but no change in idle. Now when it's cold it idles around 750 in park and roughly 600 in drive. Another thing to note is that it stumbles until it reaches maybe 140 degrees F (drops to 400 rpm). Once completely warm my idle is about 520 in drive and 600 in park. even when i tried to turn up the idle with the repair manual it began to surge and run rich to the point it was burning my eyes.

parts under a year old:

cap
rotor
wires
cts (ecm)
fuel pump
spark plugs (platinum)
maf
tps

 

Did you remove the throttle body & clean it?

 

yeah i clean it everytime i change the filters.

 

I don't know if this will help but...When I changed my IAC I had to 1. let car warm up for 5 minuets then 2. I reset the computer/removed the ground from the Bat. for 15 seconds then 3. Started car and let idle for 5 minuets then 4. Drove car at normal speeds/ stop and go for 10 minuets. This is the best way to reset the IAC. Its also the way it says to do it on a NSB National Service Bulltin. My car ran like crap after I bought my new IAC untill I did it this way! If you reset you IAC and it still Does what it's doing then you should look else where... Hope this helps a little..Oh yea...is your o2 senser good? That can cause the car to run super rich and idle funny too and sometimes our old cars dont throw codes to let us know there messed up and not working right.

 

fasteddi, not on an 85. Plain and simple. 90-92 cars use a different ECM which requires an idle learn to find the position of the IAC to calibrate fuel and spark tables.

OP, look for a vacuum leak... Especially with the nylon bypass idle air tube that can't be replaced with a factory part. Check all of the rubber nipples on this tube and also that the PCV valve and hose are seated properly.

 

Sorry about the bad info.... I didnt think about the age of his car before i wrote what i did...vaccum lines are prob the starting point to look for a problem, which there are alot of places to look...

 

i'd check for a bad throttle position sensor. also, make sure your timing is set correctly.

 

Added some octane booster which kinda diminished the stumbling and low idle...so do i need to add more on the next tank?

 

I'd get the injectors cleaned, take it to a shop that hooks the cleaning machine or canister to the fuel rail. That way the car runs on 100% cleaner. Make sure they do it when the engine is hot.
I bought a cleaner kit, I have around $100 invested in it, I clean mine every other year. I use Seafoam, BG44, & OTC cleaning fluids.