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

Welcome TurboZo,

This might help
Resetting your Air/Fuel Mixture Ratio

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

>
lol. Whats up with alot of the 99 GT's being owned by people wives?

might be the aic or the o2 sensor.

>

haha. well for us, my wife originally wanted an eclipse but I said no way since they have such a horrible track record in terms of reliability. I was thinking of the newer celica but my wife said they look too boxy and guy-ish...on the other hand she said the older celicas are curvy and (you guys are going to hate this) feminine. So I got her the last year of that generation.

we really like this car and would love it if it wasn't for this damn idle problem.

-Zo

In my case, Low RPM and almost stalling was caused by a malfunctioning O2 Sensor.

>

which one was it in your case, the one on the exhaust mani or the one further down?

thanks,
zo

Well the 3S-GE only has one since it has a 4-2-1 exhaust mani. So it was the one further down between exhaust mani and cat. But I think a local garage/dealer can find it out for you.