mb31454

Thanks Denny... I think the ICV is at the front of the throttle body, behind the tray with spark plug wires. If that's it, the problem i hear is that the little screws need a # 3 screw driver and sometimes a small vise grip to break free or else the heads strip out. You mentioned this in an earlier post and that made me think it might be stuck open or not fully closed. Yesterday, the car idled for an hour or so before the idle started oscillating up and down between 200 and 400 rpm. After that, about all I can think of is the ecu/ecm behind the glove box. As for the small hole in the throttle body, i might have seen it yesterday, but i spent most of my time cleaning the two flaps in the throttle body. As for the MAF, I try to be gentle with that assembly, but that hard plastic doesn't let go easily.

Mine will run an hour or so sitting in the garage, idling fine and responsive to throttle, prior to the idle becoming sporadic. I initially ruled out the IAC, since idle when cold was good, but from an earlier post, if the IAC is stuck open, too much fuel can be an issue and I'll pull it this afternoon and update what i find.

Have a 1991 ls400 that idles well when cold. Once the temp rises to normal operating temp, the idle becomes erratic on the low side, stalls and dies. Changed out the water temp sensor, cleaned the throttle box, air filter is ok, fuel filter is new, pcv valve is new.