Originally Posted by CamaroJoe
Anyone have anything else to add? Are there any good diagnostic tools that I don't already have that I can pick up to help me out?
My 88 s10 does this but only on a cold start.....
Does it get better if you get the RPMS past 3000 then let it go back to idle??
How are you reading TPS voltage and so on? Multimeter or ALDL?
If you don't have it already you may want to invest in an OBD1 aldl cable to connect to your laptop/computer to see what the ECM is doing....
A lot of times the problem can be pinpointed just seeing the data that the ECM is putting out..
I know you said you did propane, but take brake parts cleaner or starting fluid, squirt it along all vacuum lines and listen for a rise in the engine, propane doesn't always do it in my experiences.
You may also have something simple like a bad distributer cap/rotor/module, or a loose wire somewhere.
Also check the MAP sensor, my truck runs like ASS with it unplugged, or faulty....
But the ALDL stuff with winaldl would probably be a quick/easy way for you to determine it for this time, and future times you may have issues.,