okay so i bought a 94 toyota p/u with a 22-re about a week ago and it drove home fine and was fine for the next few days, then 2 days ago i was sitting at a stop light and the check engine light came on and the idle started fluctuating up and down, im assuming its the IAC valve? thats what it was in my civic when this started happening in that.

is there anything else it could be? vacuum line etc.

its also been brutally cold here since it happened and hasnt warmed up since (5 to 25 degrees BELOW zero) so could that have anything to do with it?

 

It could be that just check to see about vac leaks and verify that the IAC valve it functioning correctly as well good think is that 22re parts are cheap!

 

Except I've never read about one of our IAC valves going bad. Could be a bubble, could be a frozen line, broken line (course you'd really notice if it were leaking.

First and foremost, pull the codes. The computer has something to say about what the problem is, see what it says.

 

boom.

 

Is it still doing it? Mine did it one time at a stop light I drove the rest of the way home and it never did it again...

 

does it only surge while holding the brakes?

if the idle is too high the ecm will kill the injectors while the brakes are being applied.

just thinking if you developed a vacuum leak that caused the idle to bump past the acceptable rpm.

 

This can happen when the IAC , idle air control valve fails or has a leaking air hose.
Happened on my engine ,was a broken wire!
Idle would go up & down from 900 to 2,000.