1st post...low idle problems..help please Options

[TurboZo]

Hi, glad to find an active forum for the 6 gen celica...

I've had our (my wife's car) 99 GT for 3 years now. Since I've had it, I've been struggling with the low idle problem. On start up, the engine often stalls since the RPMs aren't high enough. At first I used to slightly hold the pedal until it warmed up. After taking the throttle body off, cleaning it, cleaning the ISC, testing it, the cold start worked for a while then started having the problem again. Currently, when starting up, it idles around 450 and feels like it will cut out. Once in a while the idle seems correct though soon it goes back down. with the AC on, at a standstill in D (auto), it starts to chug a bit since the idle is so low. Recently, I gave up and took it to a trustworthy mehcanic...he did a fuel system cleaning along with the intake cleaning. afterwards, the idle worked great...at cold start, the idle went right above 1k then eventually came down to 750...that lasted a whole 3 days...and now it is back to as I mentioned before. This issue has been driving me nuts for 3 years. I'm considering doing the seafoam manuver today.

Other things that may be related:
-some smoke at startup (perhaps aging seals, or pcv valve, or something else?)
-the engine temp stays low for quite a while, not staying at the midway mark like it did before)

Any input would be much appreciated.
Thanks,
Zo
99 GT
145k
auto

[Bitter]

check the engine coolant temp sensor, check the IAC motor, and check the wiring that runs to and from all of those.

[TurboZo]

check the engine coolant temp sensor, check the IAC motor, and check the wiring that runs to and from all of those.

Thanks for the suggestions. Is there any additional info on the IAC Motor? Does this forum have a link to an online Repair Manual. I've been using the MR2 one (mr2-tech.com)

Thanks,
Zo