Hey I have a 1991 Toyota Pickup 4x4 with an idle surge that I can’t diagnose. It’s got the 22re and I rebuilt the throttle body, got a new iac, replaced vacuum lines, replaced tps, I just replaced the brake booster, it has a smog delete and an egr delete. The idle surge starts when the engine is cold and stops when it gets up to temperature, and there is an idle surge when the brakes are applied. I’ve looked everywhere and couldn’t find anything. Any help is much appreciated. Thanks!

 

Low coolant causes idle surge on 22RE engines. When I was having the same type of idle problems, replacing the IAC fixed it, but you said you already replaced it. When my idle was too high, it would surge randomly with the brakes applied. It was the fuel cut RPM doing what it's supposed to do.

http://htftp.offroadsz.com/marinhake...45fuelcutr.pdf

Check all the hoses for clogs that go to the IAC. Some times people over use RTV, and it can cause clogged or partially clogged hoses.

 

Sorry if I am of not much help, but for my rig, my surging issues seemed to go mostly away after a thorough throttle body cleaning. I think maybe some of the vacuum ports on it can get clogged up over time?

 

Yes, they can. All of them can. Especially the three on the front. A quick cleaning procedure is to stick a small tube, like what the carb cleaner comes with, and give it a good squirt. cleans those ports right out. Quick and easy. Make sure that the vacuum lines are clear, too. A quick blow through them will tell you right away if a line is clogged.

Good luck!
Pat☺