i have a 83 engine and chassis with a 81 body and cab and swaped wiring harness .now the truck starts fine choke seems to work fine but after it warms up it wont idle. but it doesnt do it all the time it comes and goes so its hard to try to work on it . when its acting up the motor skips going down the road if the gas peddle is barely pushed, but push it to half trottle it stops. all vac lines are hooked up and seem to be right by haynes book. thanks for any help.

 

I would clean up the fuel system to start out. New fuel filter, make sure the pump is working correctly and clean your carb

 

Did you get this fixed yet..?
Are you running stock carb or otherwise?