Jayss01

So recently picked up a 01 rx300 and just recently noticed that if i happen to floor it that once i let off the idle will hang. If im in "D" it will idle at around 1500 rpm and the car will increase speed by itself if im not on the brake. If im in park or neutral the idle will jump to around 3000 rpm. I was thinking a vacuum leak however like i said it only happens if i floor the car, if i just drive around without getting on it at all it drives fine. The car has a CEL on for the bank 1 o2 sensor however i highly doubt that would be causing this issue especially since it is somewhat behaving like a vacuum leak or maybe a sticking iacv.

Jayss01

Well i went ahead and cleaned the iacv it did help out with the idle some however i haven't had a chance to get on it yet to see if the car still behaves weird after flooring it.

salimshah

It takes a bit of driving (engine running) for the ECU to adjust to the new norm.

Idle is totally self governed. It takes input from multiple sensors to establish the idle speed.

Also check your coolant level [pop the radiator cap with engine cold] and do not simply look at the overflow.

Salim

Jayss01

Just a lil update to this...was able to accelerate hard with the car a few times and it seems to be normal now, no more insanely high idle after flooring it. So i guess cleaning the iacv did the trick.