engine almost stalls when oil cap is removed?

[94tegRS]

alright, I replaced the headgaskets recently, while I was in there, I also replaced the water pump and timing belt.

anyways I pulled the heads because of mixing oil/water.

just the other day I had to replace the radiator because the plastic cracked, and while under there I figured I would pull the oil cap to see if there was any froth on it?

the engine was running and when I pulled it the RPMs drop WAY down like its going to die, somewhat steadies itself, and then when I put the cap back on it goes back to normal.

I did replace the PCV valve along with everything else.

is it normal that the idle is so dependant on a certain amount of crankcase pressure?

[javatrooper]

I had recently picked up a Mazda to fix and sell. The guy buying it did the same thing and the car almost stalled. I have never removed an oil cap on a running engine before so I didn't have any answers for him. He bought it and that was that. As far as I know the car ran fine. I would like to hear from others though.

[JOET/CAMRY]

Originally Posted by 94tegRS

alright, I replaced the headgaskets recently, while I was in there, I also replaced the water pump and timing belt.

anyways I pulled the heads because of mixing oil/water.

just the other day I had to replace the radiator because the plastic cracked, and while under there I figured I would pull the oil cap to see if there was any froth on it?

the engine was running and when I pulled it the RPMs drop WAY down like its going to die, somewhat steadies itself, and then when I put the cap back on it goes back to normal.

I did replace the PCV valve along with everything else.

is it normal that the idle is so dependant on a certain amount of crankcase pressure?

You don't mention the year of the camry. what engine does it have.

I took the oil cap off of my 1989 Camry 3sfe four cylinder engine when it was idling and the idle stayed the same. just little bit of oil would spit out on occasion which I assume is normal.

JOET