I just acquired a 93 F350 w/EFI 460 and 5 sp. When I let off the gas to shift gears the engine does not respond immediately to the closing of the throttle. It maintains its current rpm for a second or two and then idles down. The throttle linkage is not sticking. Any ideas? This is annoying.
Thanks,
DannyP

 

i had the same problem with my 351 windsor. Apparently underneath my butterfly valves, there is an electronically controlled bypass valve that lets a gust of air in just after you let off the gas. That keeps it from dieing. However mine was sticking real bad and wouldnt close right. So I unplugged it.

If you see what looks like an air bypass going around your butterflies with a wire connected to it, disconnect it. But be carefull it might kill your engine after you let off the gas. Hasnt happened to me but gets real close.

Its better than listening to it rev up to 2000 rpm for 5 seconds.

 

I have been informed on another board that this is a built in "feature" that reduces emissions. Not sure if that is so but it sure would suck if true.
DannyP

 

ya you do need it for emmisions testing, its required to operate correctly. But since its a simple plug unplug situation, just plug it back in when you go in for testing.

It wont make much of a difference on what actually leaves your pipe, but is needed for testing (given the tester knows what hes looking at, or cares)

 

I do not plan to disconnect the idle air bypass valve. It serves a useful function when the engine is cold or when the AC kicks in. It helps keep the engine at a steady idle. If this is truly a built in function then if I can't find another way to defeat it I will have to grow accustomed to it. I live in the hills of Kentucky and am not subject to emission testing.........yet.........Thank God!
DannyP