94 LC Possible IAC issue(Idle air control valve) (1 Viewer)

[JDennison]

I have a 94 Land Cruiser that will run good but as soon as it is at running temp the rpm will surge real low and jump back and forth. It just recently started getting low enough to where it just stalls/dies. I first thought it was the mass air meter so I put a reman in and tuned it a tad(it was a 93 camry reman, fits perfectly, was just to lean etc) but it is doing the same thing it was with the old meter,(with the addition of it stalling occasionally). I pulled the plug on the IAC and started it and the idle shot to 2k rpm and began surging from 1k rpm to 2k rpm. I plugged the IAC back in and it continued to surge for another minute and then went to a normal rpm(which allowed me to drive the rest of the way up my drive and to my parking spot.) I feel like I need to add that the reason I though the issue was the mass air meter was upon cold start up I had to press the gas multiple times before it started, and after puttong the reman on and adjusting it, it starts every time, the other issue just shows its face at operating temp.

 

[voodu3]

This might help with tracking down the issue.
Also Check the condition of the air intake tube they can get small cracks in them especially on the underside from years of heat That can cause the surging from unmetered air getting in. I would check the timing if you’ve had the distributor Cap off to replace the o-ring. Lastly check the accelerator cable. Adjusting it to get your idle set and that it moves freely.

 

[fjbj40]

With ISC disconnected it will go to 2000. After you have it running and you shut it off you should hear the IAC cycling, clicking like sound, this is normal. The IAC, after shut down, goes to full open. This causes leanness on start, wanted to increase start-up rpm. But it should not go to 2000, it should go to about 1200 rpm at first start, as the IAC starts closing when you start motoring to start. If there is a carbon build-up on throttle plate or IAC seat rpm will be higher at start.

There are checks in the FSM for it.