Hey thirdgeners, I was wondering, what is the best idle speed for these 305's? Right now mine runs at about 600 rpm, but sometimes it decides to run at about 900.600 seems low to me and when it runs at 9 it seems to have a lot better throttle response. I know some have there's set 2 degrees advanced and that's what I'm thinking I should do. But what would that bring it up to? Also, if my idle is always changing, sometimes its high some times its low, would it mess anything up if I were to go advanced?

Thanks,
Matt

 

Idle speed is set, unless you drill out the cover to the screw, no way to adjust it manually. I'd be looking at a sensor issue (maybe IAC or TPS?).

Stock, LO3 idles at about 600 in park, about 500 - 550 in gear.

Changing timing won't affect idle (as long as the ECM is doing it's job) because no matter where you set it (within reason), the ECM will adjust it back down.

 

look in the tech articles on how to set the tps sensor and the iac. if it is stock set the idle to 500 with the iac unplugged. actually you can go a little more. then make sure the tps is in range. .48 to .64 volts. i had brian at tbi chips set the idle to 650. so i set my idle to 600 with the iac unplugged and she idles perfect at 650.

 

This is the article he's referring to. Lots of good stuff in there worth a look.
https://www.thirdgen.org/tpimod2