Hello all. I am a newbie here. Hope somebody can give me some advice. I am working on a 1991 Toyota P/U 4x4, with the 3vze. Just the other day, the motor started to surge or hunt at idle. Just like a small engine with a governor problem. The rpm's bounce between 800 or so and 1500. On top of that, the engine started to ping while under load. After the motor is warmed up, the rpm bounce stops....until I drive it and come to a stop. Then it's back. Here's the strange part: after idling a few seconds, the surging stops BUT...if I hit and hold the brake, it comes back. What gives? I am lost and have no clue where to start looking. Any help would be greatly appreciated. Thanks.

 

any check engine lights? or stored ones without the light on? I would start there.

 

No trouble codes at all. No stored codes. With E1 and TE1 shorted, it is normal.

 

with it running normal with your timing connectors shorted and with pinging a rpm change I would look into testing the knock sensor. But I don't know the 3.0 all that well so I could be wrong, but I guess it wouldn't hurt to test it.

 

Have you checked all of your vacuum lines?

 

Yes, checked all vacuum lines with a stethoscope. No leaks or cracks. Could the AAV on the throttlebody be causing this?

 

Thanks to all that helped. I ended up reading thru alot of other posts here, so I cleaned the throttle body and the AAV and was able to adjust the idle down to 800 rpm and no more surging. Thanks much.