1st let me say thanks for the help with my choke problem. The choke works fine now. The problem now is that the motor is slow to return to idle after acceleration. I thought the throttle might be sticking, but I went out and revved the motor up by hand with the throttle linkage, and it snapped back quickly. I even closed it by hand just to make sure it was closing complety, and it did. After the thottle is closed, it takes the engine about 4 or 5 seconds to return to normal idle. what would cause this? this is an 86 351w HO 4 barrel motor in my 1978 f100. thanks once again, Ben

 

Wow. I could tell you what to look for right away on an EFI motor, but that is some pretty bizarre behavior on a carbed motor. The only thing that I can think of off the top of my head would be a serious vacuum leak.

 

2 questions...
Is the secondary throttle plate staying closed (and adjusted properly)?
Is there a dashpot on the throttle that is doing this? Some calibrations use this feature to keep the exhaust from popping (sounds like a backfire) when the throttle is closed.

 

cjben, what you are describing is also a classic sign/symptom of a vacuum leak. Check all hoses, carb bolts, intake bolts, make sure nothing is leaking vacuum.

 

thanks guys. i will check for vacuum leaks again if it warms up today at all