I am having issues with my throttle not going to idle when I let off the peddle. This is on my 92 4runner with EFI. Today my 99 Tacoma started doing the same thing. Idle won't drop below 1500 rpm unless I put pressure on it at the throttle body linkage. I have now put heavy return springs on both for a temporary fix, but is this a known issue with these throttle bodies? Could it be the position sensor?

 

Have you tried cleaning them?

 

I've never heard of it as an "issue." Odin's question about "dirt" is the direction I would go. Try disconnecting the throttle cable, and work the the throttle by hand. If the problem goes away, I would suspect the throttle cable.

 

Also I don't think I'd run those HD springs for long. The extra pressure could accelerate throttle shaft wear, at least it does on carburetors. On carbs the extra shaft play lets in more air at idle and you end up scratching your head looking for vacuum leaks causing lean mixtures and higher idle speeds.

 

yes the throttle body was cleaned. I just put together the 4 runner, it was a body with everything else in boxes, so all the parts have been cleaned. It hasn't even been out to register it yet, gotta get the bugs out first. the cable has slack in it so I know the cable is not binding. Seems like the TPS is what is binding, but not throwing a code.
The Tacoma hasn't been touched I will try cleaning it and see what happens. There seems to be a whistle that comes and goes also and I can't seem to find where it is coming from. Not that many hoses on the Tacoma.

 

The dashpot could be stuck, back it off and see if that works.

 

Found it, a piece of electrical tape somehow got sucked into the throttle valve. I have no idea where it came from.