I have a 92 pickup with a 22RE and manual transmission, it currently has a motor out of an 89 in it. I just replace the TPS and the circuit opening relay to correct a couple of problems I was having with the fuel system. Those issues are now corrected. I seem to have developed a new problem however - when driving the truck, say 2500 rpm and then stop, the motor does not want to return to idle (750 rpm). It hangs up around 1700 rpm. If I "blip" the throttle to about 3000 rpm the motor returns to idle fine. If I hold the throttle at 2000 - 2500 and then let off it hangs up a 1700 again. This happens under load and not under load both. The motor is properly warmed up when this is happening. I set the TPS according to the FAM and base timing has been set correctly. Any ideas? Thanks in advance.

 

Throttle shaft or cable sticking maybe?

Dashpot getting vacuum from the wrong source?

 

I did some additional reading after posting this and came to the dashpot. I'll be checking it tonight. Thanks for the suggestion.

 

I have (still) the same problem in my 4runner 3vze.... will surge or maintain up as high as 2000rpm until you blip the throttle. dashpot is my guess, greased and lubed the crap out of the cable.

The other funny thing is that it usually only happens when I drive it, not near as often as when my wife drives it. we both mush the thing hard too...

 

Ok, so I checked the dashpot and it seems to be the culprit. Under any "normal" condition it won't allow the throttle to fully close coming back to idle speed. If I push the throttle back to closed, the motor goes back to idle or if the throttle is "slapped" shut ( ie: 3000 rpm rev and quick let off) it returns to normal, but any sort of normal operation of the throttle and the dashpot stays "out". I tried spraying it with silicone inside the dashpot to free it up but to no avail. The FSM doesn't say anything about an adjustment if this happens. Any ideas other than "buy a NEW one"?

 

Take apart the dash pot or whatever that little throttle plate dampener is called. It's a couple plastic cups, a rubber valve, sponge and spring. Take it all apart and dry the sponge.
I did the head gasket on my 22re and I ended up soaking the dash pot with parts cleaner. The sponge soaked up the cleaner and it wouldn't let the throttle return very easily.