ok, so I'm pretty new to this forum thing. I have been doing a lot of research on this issue and i cant see to find anything to help me.
I have an 89 s10 blazer with a 4.3 in it. when I start it whether it's hot or cold it goes into high idle(no idea how high as it doesn't have a tach). it sat for a long time before I got it so they first tank of fuel I put in it I added a can of Berryman's. then I took the throttle body apart and cleaned it. yes, i put new gaskets in it lol. I changed the tps and the air filter...plugs..wires..the norm. temp gauge is working just fine. I even did the carb cleaner vacuum test and found nothing... I'm stuck...any help would be appreciated but I don't have hardly any money to put into this thing...

 

Can you advance a bit on the version and engine please? Need a bit more specs.

89 - Carb or injection?

If it is fuel injected which type? (IMHO all pre 1993 fuel injection were TBI)

If it is fuel injected what does your coolant temp sensor say? The fuel injected may have two sensors. One for the gauge and one for the fuel injection. This could be one cause of high idle.