Surging Idle

[zppeacock]

my 1990 camry wagon will surge sometimes I have found it to happen when the motor is fully warm and if I idle around a parking lot for about 10 minutes.

Anyone have a clue on this?

Sorry about the typing I'm on my iPod.

[Doctor J]

Need some clarification:
Are you talking about fluctuating idle speed that goes up and down while the car is not moving or about engine revving up in pulses every other second while decelerating with throttle closed around 40 mph?

[white90dx]

Originally Posted by Doctor J

Need some clarification:
Are you talking about fluctuating idle speed that goes up and down while the car is not moving or about engine revving up in pulses every other second while decelerating with throttle closed around 40 mph?

Ooooo!!! what's the deal with the second one? My Alltrac does that (only around 30-35mph - different gearing on the A540H, I suppose?). It doesn't really bother me, but I'm curious.

-Charlie

[Doctor J]

I "fixed' this on my 87 wagon and another 87 sedan by cutting the speed sensor wire near the engine ecu.
this action changed the fuel cut rpm to 1500 instead of 1200 with warmed up engine.
so far I have not found real repair for this, however many camry owners are aware of this problem.

[zppeacock]

doctor it's the first symptom

[Doctor J]

Check for the intake vacuum leak , if none found you may have to try cleaning the throttle body and/or idle speed control valve.

[zppeacock]

No vacuum leak, I used a smoke machine. And I cleaned the throttel body in the spring and it still looks spotless.

Where is the idle spped control valve?

[Doctor J]

under throttle body

[zppeacock]

Do you have a picture or diagram of this?

[disregard]

a picture would defiantly help us here. I have the same problem.

[Doctor J]

It looks similar to this one [92 shown]