Stall/Miss When Cold - 2000-3500 RPM Idle When Hot

[1987 GMC Jimmy]

.....

The hard part will be not popping the hood for say, three days to see if the "fix" worked.
Try not to mess with ANYTHING until you find confidence. In the world of automotive repair, if there are no issues after three key starts, it's fixed.

I've driven it about fifty miles, and it drives great. It does idle kind of ****** when I first start it and disengage the fast idle after a moment, but only then. I pull up to a stop sign after driving it and purrs like a cat. The idle speed screw is backed all the way out because I wanted a low idle so I can up that if need be, and I'll try to readjust the curb idle mixture. The dwell on the MCS was set to spec when I had it rebuilt so I'm not worried about that.

 

[1987 GMC Jimmy]

Gave it about a half turn more of idle mixture and tightened the idle speed screw a little bit. It's almost perfect. I say almost because there's no such thing as perfect on a 31 year old car.