Leeroy

Hey guys, so I have been fighting with a low idle on my car for a few months. I suspect it to be power steering related, ie: idle up valve, dirty rack solenoid, but a shop that I took the car to said it's the IAC motor. I have never thrown a code for that particular problem before. Does my car even use that part? Or did it go away when the updated to VVT on the 98+ models? I don't trust what these guys are telling me. Thanks in advance! BTW, I've already replaced all 4 O2 sensors, changed the air filter, cleaned the MAF, cleaned the throttle body and under the vacuum plate to no avail.

djamps

There's no IAC valve on '98 and up. Idle is controlled entirely by the throttle plate.

Leeroy

This is the part that he said I needed to replace:http://www.lexuspartsnow.com/parts/l...672-47010.html . I don't have any surging problems, just a low idle when in gear and stopped at a red light.

djamps

How low of an idle? If it's not stalling I'd suggest replacing the motor mounts to absorb any vibration. Mine seems to idle pretty low in gear with the A/C off but if it weren't for old motor mounts I wouldn't even notice. The motor/trans mounts go out every 80k miles or so based on my LS's service history, and it's long overdue at this point.

Legender

When is the last time you cleaned the throttle body? This cleaning of the body and the butterfly valve could really improve your low idle if you've not done it. Mine was so low on my 95 that it usually died when coming to a stop after a trip on the highway. Cleaned it and it solved the problem.

Leeroy

Yeah, I have yet to replace the mounts on the engine. I should do that. I have cleaned the TB and butterfly twice and reset the ECU both times. No difference. I am really leaning towards a vacuum leak on the power steering being the culprit.

djamps

FYI a vacuum leak will normally increase idle - not lower it.