hope i can get help here,
i have just transplanted a reman. 1978 350 into a 1991 chevy truck. i got a adapter plate for the stock tbi. will start and run fine untill it reachs opperating temp. then has a slight miss at highway speeds, and WILL not idle. just dies. will start up fine, but dies again. about to go back to the carb.
i would rather use the tbi. dont know what i am doing wrong. it worked fine before the engine swap.

 

since i have replaced every gizm and gadget and hoses, and i got no reply. i figured to go against the shop tech i have been bugging, and tote apart the tb. people i think we found the problem. darn think looks like it has been at the bottom of a lake. needs new regulater. the spring itself is in 7 pieces! ha.

 

You may want to try checking the ECM for codes and possibly using an ALDL cable on a laptop with WinALDL to see what is going on.

Did you swap the same size engine? Same cam, same heads? Is everything stock?

 

i have replaced or rebuilt everything for this stock tb. the engine that sits in this truck has been factory refurbished. (1978) i have no idea about the heads being the same as the engine that i pulled out of this truck, nor the cam. all i know is that they are both 350 cid. i still have the old spead bore intake on, with an adapter plate for the tb. it will idle if i remove pcv hose from tb. nothing is making sence with this at all. also replaced the ecm. i have no vaccume leaks. acts like not enough vaccume. ????????????????????????????????????????????????????????????