1992 Full Size Blazer 5.7L 350 small Fuel Injected! It seems that my truck is having idle issues. In park shes at about 900Rpm but when I go into drive the engine goes as low as 200 and will stay there its not boggy very smooth but very low, on another note this might even be connected my voltage gauge jumps around from time to time. Alternator? Battery? Any help would be greatly appreciated. Christian Cauble

First time post.

 

Does the voltage swings occur when the idle is low?

 

Yes, its seems so.

 

Have you cleaned the IAC valve in the throttle body?

 

I havent, do you have a suggestion on what to use?

 

off the subject is that your 74 in that picture with the tahoe?

 

Just get some carb cleaner.
Its a round sensor on the left side of the throttle body. Use a pair of channel locks to unscrew it,spray the little piston down with the cleaner until its clean,also spray a little inside where it screws into,and use a old toothbrush (not wifes,she gets really pissed off) to help clean the inside.

 

As chris wrote, just remove the IAC valve and clean both the valve and the bore it goes into with some carb cleaner. Get the sensor safe stuff which should be all that is available now. Some of the old stuff could damage O2 sensors if sprayed into a running engine.

They both are my vehicles.