Fluctuating Idle (by the second!)

[fernden]

I have a 1990 Camry 4 cyl. that I just got from a guy. It seems to run really well. So far, I've changed spark plugs, wires, distributor cap, rotor, fuel filter, air filter, and cleaned throttle body. However, it's been doing something I'm not sure how to fix. When it's in either "Park" or "Neutral" the idle fluctuates from about 1000 to 1500 about every second! It did it today whenever I'd put the car in "P" or "N" but then I went in to the restaurant and came out and it had stopped doing it altogether. So the problem's intermittent. Any ideas?

Thanks.

[atobe]

check those vaccum tubes.. could be clogged or leaking

[fredk]

it is called hunting, its trying to compensate for something, check the vacuum hoses and the big intake hose for cracks and get some carb cleaner and a rag and clean the throttle plate area

[fernden]

Beside being able to just visibly see cracks, how can I check vacuum hoses and air intake hose for leaks?

[Doctor J]

By spaying connectors with WD-40, it will temporary seal the crack causing idle to smooth out.

[toyomoho]

Or use a small propane torch with open valve but not lighted, engine speed will pickup.

Also check IAC valve and MAP sensor.