Toyota 4AGE Engine: Floating Idle Problem (Corolla AE86)

Here is a video of my Toyota Corolla AE86 with a floating idle problem. The car starts well, no check engine light, but the idle starts floating after a while..

Constructive suggestions and comments are more than welcome.

Filmed with Sony DSC-WX9

[MoleskineFan]

Thanks a lot for your input, I will start by burping the radiator. I already have a brand new radiator cap ordered at Toyota. I will post a new video of the procedure!

[MoleskineFan]

I will check that after I bleed the cooling system again! Thanks!

[XarsVariety]

I see this is an old post, but in case anyone else is looking. I have a AE92 Red top 4AGE and it would do this, even sometimes when the weather changed. I just turned the idle down... I believe that's the TPS like posted below. I think I brought it down to like a 1.5 cold idle, and it was fine in the winter. In the summer I would have to raise it a bit since the cold idle is not as high. I see your idle was like at 2.1ish. That's all I did and it pretty much never bothers me. The associated problem for me I guess is I still can't run the A/C without the car dying or really struggling.

[MoleskineFan]

I will start with the most basic procedure - bleeding the coolant system again. And then move on to more complex diagnostics.Thanks!

[Mathiasvideo]

The TPS, throttle positioning sensor must have been modified. if that's not the case, check your AMS, air mass sensor. if you start the car and unplug the AMS, and the car dies, then you know your AMS is working, but if it's been missed with, then I'd check back with what you've missed around with. Too many hands in things can cause more problems. TPS is a know flux like this and if you drive it won't let you rev as high as you need for correct driving because it will want to stall out. Idle Assistant Sensor, or IAS will also cause issues. But i've seen this same similar issue at any idle out of the TPS. What did you do in the order you did it that cause this or when did you see the problem. Write you list. Get your order right. Good luck.

[carloscicly]

Hello I am from the country of Peru, I have the same problem, what is the solution? Black smoke comes out of the exhaust pipe, the engine has been repaired, I have this problem, can you help me?

[timstewart]

Did you ever solve this problem? My 97 4AFE is doing the same thing.

[abrahimaljamal]

My 4age not working from first time should i try many times ! Any info plzzz ??!

[samsukkarieh]

hey man did you find the solution i have the same issue?

[HelderFontesPT]

You forgot to mention that this happens even with the temperature sensor disconnected, although with it disconnected it turns on a check engine light.

I think if it was that sensor or something with its wiring, with it disconnected the injection computer wouldn't know the engine temperature but should not turn the idle up and down like that. But, of course, I'm far to be a specialist on this. Good luck finding what is causing this problem.

[Ae]

It's tps. Replace it. It will stop. Or you can just unplug tps you'll see it will stop floating. But do get a new one lol. Just fix mines. But now it's doing some other stuff. Starts fine than out the blues it's starts to idle down, up/down to the point car dies.