irregular idle

[skathed]

My 2JZ-GE keeps turning over and idling at diffrent rpm's sometimes its 900rpm other times its 1900rpm then when moved into D it drops down to normal. occationaly when driving it wont go below the a certain rpm which is annoying as i need to use the brakes heavily to make the car stop. is this a sensor causing the issue?

[Lloyd]

Vacuum leak? Did it just start all of a sudden or progressively got worse? Does it have water in it?

[Adoom]

I have no idea about the 2JZ-GE, but this stuff applies to most engines.

It must be getting extra air past the throttle body causing it to idle high.
Is something preventing the throttle butterfly from closing all the way?
Are there any pipes coming off the plenum that are leaking, or connected up wrong?
It must have an idle control valve, or something, so the ECU can control the idle. If the crank case breather pipes go back into the intake, the idle control valve could be full of carbon build up making it stick. Can you take it off to look? You can clean inside it with carb cleaner.

Can't think of anything else.

[skathed]

will have to look. im new to jz engines. will have to take it apart. i have crc carb clean at home will it be ok on it?

[crispy'86]

Also check to make sure it's not a faulty thermostat, does the coolant temp gauge move up or down depending how far you drive? This could do this also