Does anyone know the proper order for performing the "tune up" procedures? Do you set minimum air first, or can timing be done before that? Is there any way to alter idle speed, assuming that any of the tune up specs are out of whack? Also, will crap in the IAC passages cause idle problems? Just wondering. Thanks to all who respond.

 

Since you should go to base timing and no IAC active while setting the throttle minimum air position, the base timing should be checked first. It can affect the base idle RPM.

IAC air passages and an IAC stepper motor that are dirty or restricted can cause a low or wandering idle speed. It would be good to clean the IAC and air passages before setting the minimum air position just to be sure the IAC is fully closed when teh throttle position is finally set.

Of course, once the throttle position is set, the TPS voltage shoudl be readjusted if necessary.

 

Thanks for your response. That's kinda what I figured but I'm still trying to pin down why I'm getting this weird intermittent popping or backfiring on deceleration. I hope the guy who did my chip got the injector flow constants right (19 to 24 lb/hr. inj. swap) I hear that this happens when the engine goes a little lean upon throttle closure. Anyway, thanks for the tip.