Chevrolet Repair: 1985 S10 4x4 4 cyl idle speed, throttle body injection, air control valve

Question
I just bought the old truck to kick around in. It is fuel injected with a carb. It idles much too fast. The screw that I thought might idle it down does not help. How can the idle speed be adjusted?
Thanks,
Robert

Answer
Hi Robert,
Let's see....
1985...fuel injected...and carb.
Something doesn't seem right.
85 is borderline before fuel injection was common, especially on GM trucks.
But it may be FI.
Wouldn't be FI and carb, though, so I would say throttle body injection, which looks like a carb, but has injectors at the top of the throat. In that case, there is an idle air control valve, which is cleanable with carb cleaner, but not adjustable...it does that itself.
Now, if it has a carb, the choke linkage, and idle adjustment screw, along with the ignition timing is where you work.
Make sure all the linkage is free.
There may be an electric idle motor also, which is adjustable.
Van