I just purchased a 1980 f350 custom dump truck km having some issues with the way it idles now I put a new carburetor in it and plugs and wires and I also adjust the idle screw on the back of the carburetor but it's still idles really high and sometimes when I stop at a light or stop sign it's idling so high I have to shut the truck off before something happens any ideas???

 

more info may help here, what engine, transmission, what carburetor do you have. is this a 4x4?

 

It has the 5.8l motor it's manual transmission and its 2wd its a dually though and the carburetor is the 2150 carb

 

I'd start by looking for vacuum leaks.

 

Thanks I tried that I can't find anything leaking anywhere I think I might have figured it out but now sometimes when I shift into 4th gear it coughs and sputters idk what the issue is now it's driving me crazy