Weird idle

Ok fellas, My RS starts fine and when shes cold idles at 1500 for about 15 mins then she goes to normal idle speed. Is this supposed to happen? Is my IAC stuck, or need to be cleaned? No engine codes either. Shes due for a major tune up in about 1 month so maybe this will fix it.

BTW...Stock 305 TBI with no mods yet.

i remeber when i took auto shop in highschool my teacher explained this to me and why it idels differnetly. i think it idels smoother when the exhaust hits a certain temperature and the loop closes what loop i dont know but it closes

Sounds like your minimum air rate needs to be adjusted. Pretty simple procedure as I recall. I did it a few years ago on the L05 350 TBI a '92 9C1 Caprice I used to own.

Go to www.thirdgen.org and check the tech articles. Thats where I found quite a bit of useful info on TBI tuning.

:cool:

hmmm...Couldnt find any info on that. Could u explain the process.

I looked again, and found this. (http://www.thirdgen.org/newdesign/tech/tpimod2.shtml)

It was a few years ago that I used the article over there for setting the IAC (idle Air Control), but I'm not sure if the above link was the exact one I used.

my 92 305 TBI idles at 1500 too when its cold, the only thing though is i have an open element air filter that doesnt recirculate engine air so my warm up time when its really cold is about 30 minutes of driving. one time i let the car idle in drive to about 40mph, and it fights braking. now that i think of it i should have that fixed before next winter :D

Yea thats what i found but i dont think it needs to be adjusted. It idles fine when warm. If i mess with it when its cold and turn it down the 600 RPM, what will happen to it when it warms up?

mine does that 2,when I pump the gas it usually stops,& comes back down to the normal Idle...............