random engine revs,wierd idle

[240sx1234]

looked at the search,but nothing i see to really answer my question
i have a 95 240sx se (stock ka24de) and hks exhaust only things ive done to the car,when the car is just sitting by itself it will randomly start to rev up and down.not to high like maybe 1500 at most then back down,it does it when i turn the wheel and turn the heat on which draws more power...i know.but sometimes it will just do it sitting there without touching it.if you need any more info to help me fix my problem let me know

[zenkifem]

hows your timing?

whens the last time you cleaned out of your MAF?

[240sx1234]

ive personally never cleaned out the MAF,couldnt even tell you where it was located?,what do you mean timing?

[mrmooseman]

also check your tps!

[SleepR 240sx]

Yea sounds most like your TPS. Check it.

[TachPHD]

Since its sitting there, I would mostly look at the IAC. Maybe clean it out? This unit usually plays with the engine rev at idle.

[cotbu]

CTS problems, have a similar effect of bouncing the rpms like the OP describes. A video or audio clip would help. Make sure coolant is bled and cts is functioning correctly, wiring etc.
Of course there could be other problems, but a code check and sensor replacement might fix you up!

[supradealz]

could be bad o2 sensor, coolant temp sensor, but most likely IAC. IAC is probably gummed up or reacting slowly therefore your ecu has to compensate, kind of like swinging a pendulum trying to hit a bullseye

[240sx1234]

CEL for the front o2 sensor is on