Idle Issue

[raptor727]

i have a 92 240sx dohc. its got about 130000 miles on it. nothing major, electric fan, injen intake. i am having an issue with the idle. the idle when im at stop lights usually drops to 400 rpms and goes up and down sometimes but usually sits at 400ish. idle goes up and down a hundred rpms. but it doesnt always run rough, sometimes smooth. feels like it might be miss firing. not sure. but like i said it doenst do it all the time. Spark plugs are a couple months old. the tips of the spark plugs are a chalky white color. when it is running completely smooth it idles around 600 or 700 rpms. im in the process of getting a new tps.

[bruinbear714]

Do you have the electric fans on constantly? You might need something like this DIF PWM fan controller if your alternator isn't putting out enough juice to supply power for everything.

[raptor727]

no they are hooked to a temp sensor

[ReX2SX]

Well since the plugs look like that, why dont you replace them. You know white plugs could mean coolant leak or old plugs

[raptor727]

i read that the white chalk is related to running fuel injector cleaner.

[ReX2SX]

Whens the last time you ran inj cleaner?

[raptor727]

couple tanks ago