Engine Idle Problem, Not like any posted before. Options

[Kadett]

I got this very strange problem. Car already been to the garage 3 times(toyota dealer). Still i have this problem (at least with a warm engine)

It started out like this:
1 day i started the engine (cold) and it would idle at about 1100 RPM(when i bought the car, it was 1500-1700 i think) . When i increase the throttle it would do that like normal but then it would go below its idle RPM (cold about 1400??) to about 400 and lower and sounded like a choking sound (to much fuel) and sometimes die on me.
When the engine is warm it would idle normal at 800rpm. And when I increase the throttle then it would go to about 3000 and let it drop it would go to 600 and then go back up to 800-900 rpm.

Theres a part already replaced (literal translation= Step engine) controls the air mixture with a cold/warm engine or something like that. Have not tested it with a complete cold engine but when i started it at the garage (engine not running for about 2-3 hours) it idled at about 1400 rpm. GREAT i said. Problem solved.

But after test driving it, it actually sometimes drops below 800 RPM again.
OOOOOOOH I am so frustrated. Plz somebody what can it be, before i push the f*&^%g car of a cliff!!!!!!

EDIT: I forgot to mention something: When the car idles at 800 and i have the lights/brake on and then turn the lights of or let go of the brake the rev go up about 50-75 rpm. Related?

This post has been edited by Kadett: Jun 7, 2005 - 10:00 AM

[Bigmeanbulldog55]

I'd be a lot happier with the 800 idiol than the 1400. That's were they are suposed to be. I've got idiol problems as well, but mine is involving the choke not wanting to stop (I think). Car idiols too high at times.

[Kadett]

No it was 1400 just for about 1 minute, then it went down to 1000->800.
But it did not go above 1200 rpms anymore before todays "fix", even with complete cold engine!

This post has been edited by Kadett: Jun 7, 2005 - 10:02 AM

[Kadett]

Bump

[playr158]

your car SHOULD idle at 800 rpm most always

[Kadett]

Well thats not the problem. The problem is that it goes BELOW that. Like to 500 rpm then goes up to normal 800 rpm.

[Negative]

Mine does that only when it's hot and humid outside - and then very rarely. My '95 did it, my '86 did it and they only got worse with age. My new one did it last summer a couple of times due to lord knows what and I reset the ECU and now runs like brand new.
I think our stock idle is slightly too low for some weather conditions but you typically have to live someplace hot and humid (oposite of Japan perhaps?) to notice it.

[lagos]

sounds to me like you have a vac leak. get a vac gauge and hook it up to see where u are at. if its low, check for any cracked of broken hoses.

when u put your your foot on the brake, you are using the brake booster sysetm that works off of engine vac. you idle should go up a little when u take your foot off the brake or turn off any headlights.

This post has been edited by lagos: Jun 7, 2005 - 3:23 PM

[mark_426]

Yeah, look for a vac leak.

Does it surge, like up-down-up and so forth, or does it only drop when you gas in then drop it?

Do you have any accessories on - ac, lights, high sound, etc? These will bog the engine down as well..

Check and make sure you have your oil cap and gas cap on tight too..

[Anub1s]

On top of the vacuum leak I would clean out your throttle body and check all moving parts in there, if you are getting too much fuel you aren't getting enough air, could just need a cleaning.

[Kadett]

It was already cleaned. Only accessories i have are my ICE install. But i had the prob before that.
About that vac leak.

How precisely do that? Check the hoses from the intake?

ECU Already been reset for 2 times. I only do 20 MPG (Even with normal acceleration to max 3500 RPM, keep in mind that i have a 3S-GE engine)!! While it should do about 24-25 MPG (city cruising)according to the statistics.

Could it be the O2 sensor?