I did a little cranking on the fuel screw today (nothing major, collar is still on) and I've got something weird going on now. I adjusted the idle back down to the normal level (maybe a bit lower...I like a low idle).

Test drove it and everything was fine until I did a WOT run. When I came to a stop after the WOT run, the idle was pretty high (around 900-1000 rpm if I had to guess) so I got out and checked it. The "throttle plate"* won't return back to it's resting position against the the idle adjustment screw after a full throttle run. You can blip the throttle some and it returns to the idle screw just fine, but if you floor the throttle, the plate stops about 3/16" before it touches the idle screw. You can bump it by hand back towards the idle screw and it seats itself again and idles just fine...until you floor it. Then you have to do the whole thing over again.

I removed the throttle arm to make sure the plate was free to rotate back to the idle screw, and it is. It just seems to be sticking slightly before it returns to the idle screw. Any thoughts?

(*or whatever it's called, it's the plate with the two holes in it...the one with the ball joint that you can move the throttle linkage to either the inner hole or outer hole to control full throttle travel.)

 

Trans Kick-down cable binding at the end of it's travel maybe?

 

i had the same problem. I just sprayed the return spring on the pump with penetrating oil and it has worked fine ever since. I'd like to know what caused this as well. Because mine would stick at WOT.

 

it should have two return springs (a dbl spring going to the radiator, and the throttle indexing shaft return spring), so if they cant manage to pull it home somethings probably binding or not lined up right. loosen things up a turn and see if it works fine then, then tighten it and see if it binds again. has your throttle index shaft return spring ever been off? might not have been pre-loaded right when it went back on...?

 

I had a very similar problem when I first started driving my truck. I could give it throttle, but it wouldn't return to idle. Eventually it stuck at almost WOT and I had to shut the truck off to kill the motor.

It was the shaft that runs through the bracket on the motor, so the actual throttle shaft There are a couple nylon bushings in there...but the shaft can get rusty and gummy and bind up. I dismantled everything and polished the shaft, re-greased everything and it works better then new.

 

It could be your TPS. When I went into my pump the TPS didn't get back on correctly and wouldn't return back to idle. When I took it off the linkage returned freely, but the TPS was ruined do to the plastic tabs being broken(if I remember correctly). So I went with the potentiometer fix and now it's better then before.

 

you have increased fuel at the same "throttle position" so for the same result (rpm) you need less throttle=same amount of fuel=desired RPM idle.

this means the arm on the IP has to go back further than it ever has to get the same result because it has worn in to stop at the factory idle setting.

if it doesn't have a return spring add one and lube it a little, i have had a similar problem.