Hi everyone,

I have a '91 4runner with a 22re. Brand new engine from Yota1, less than 40,000 miles. I recently blew head gasket (lost coolant hose on hot day. It was loose from my heater core by-pass. Oops.) I've done the head gasket job, and all is now well, however since the accident my idle has been surging. My first thought was that the AFM got messed up when the engine overheated. I've tried playing with the idle screw, I've cleaned the throttle body. The truck idles hight to start, then as it warms up lowers to proper idle, just under 1000rpm. The issue still is after engine is warm, when I apply the brake, the surging begins. could this be AFM related?!?! Fuel injectors? Brake booster?

Cheers

 

If it surges when the brakes are applied, then the idle is too high. My 92 22RE acted like that randomly, and a new idle air control valve fixed the problem.

Also, make sure you check the o-ring on the idle adjustment screw. It might be hard as a rock, and just crumble into rubber powder.