I have a '90 S10 Blazer. Does anybody know if the soft metal cover pressed into the throttle body casting, opposite the steel stop that protrudes and limits how far the shaft the butterflies are mounted on rotates, is actually a cover for the adjustment?These parts are all on the linkage side of the trottle body at the spring. Of course my book doesn't break down the throttle body in enough detail to make a good guess. Thanks.

Charlie in NC

PS: From my answer below, the cover blocks access to the idle adjust screw. Pried it out with a scribe and gave the screw about a 1/4 turn and this kept the butterflies from jamming. Don't know if where on the throttle stop or wear on the end of the idle adjustment causes this, but they sure were jamming themselves into the side of the TB

 

A picture is worth a thousand words!

 

What exactly is your problem? Throttle sticking? If so, have you tried twisting the throttle plate, spraying some carb cleaner on the side walls of the throttle body and scrubbing it with a toothbrush? These motors build carbon up fairly easily in the throttle body and you will feel it in your pedal sticking.

 

My 87 Chev Sub book had a good breakdown on the TB. That pin was just the idle adjustment, removed the cover, gave it a 1/4 turn and now the butterflies don't jam in the TB throat and stick and did not change the idle RPM. Problem solved.