not your normal high idle problem

[s13point5]

so i did a search for high idle and every one i read, it seems everyone's high idle would be all the time. mine is different. after i have driven the car for awhile, the car starts the idle really high. i dont have a tach but im guessing 1500-2000 RPMs. after the intial start up and the cold start, the car idles fine. quiet and not high at all. it only starts idling high after i have driven her for awhile. i can shut the car off and turn it back on after 5 mins and the car will go back to idling normal again for awhile. i have the TPS adjusted correctly. i adjusted the idle screw on the IACV to idle a LITTLE bit higher because she was dying on me while i shifted into neutral while coming off the throttle. timing is right. no boost/vac leaks. its really bugging me because its making my gas mileage go to ****. i do have a Q45 TB. any ideas?

[lilskyline240]

how did you finally get your TPS calibrated correctly and get your idle down? wherent you having problems with a high idle unless your TPS was set to alot lower volts than stock?

[s13point5]

i didnt really have a problem setting the tps. even when it was set incorrectly my idle wasnt really that high

[lilskyline240]

Do you have your stock PCV system still intact? With the hose from your valve cover to the PCV valve in the intake mani and the other hose to your intake? If not you could be getting unmetered air into your motor if you dont have that hose hooked up to your intake and just venting to Atmosphere

[s13point5]

yes i do. i just hooked that up a couple nights ago and that was the same night where the car drove without any problems. i was told that i need to put a check valve inline with the hose that goes from the IM to the valve cover. i just need to get one .

[lilskyline240]

well ur PCV valve is a check valve. If you dont have one of those and ur pressurizing ur valve cover that is SUPER BAD for your motor

[eh?]

The Q45 idle up mechanism removed? Is the aac valve getting power? Is the air regulator getting power?