idle issues

[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. when i start the car after its sitting for a couple days, sometimes, the idle drops and gets to the point of almost stalling, if i dont rev it up, it has stalled once or twice before. after its warmed up its pretty much good as far as not stalling. the idle when im at stop lights usually drops to 400 rpms and goes up and down sometimes but usually sits at 400ish , but when i know its running real smooth its aroun 600-700 rpms. it also has alittle blue smoke, ONLY when i rev it up and not all the time. i was told it could be bad valve seals, or a bad piston ring.

[richesmoua]

i had similar problems. I replaced my spark plugs, oil change, and notice that i was out of anti feeze coolant. when I did all that my car runs a lot better now.

[raptor727]

i keep it well maintained and all liquids are topped off. but it doesnt do it all the time.

[StandardProspect]

there is a screw on the back of your intake mani that can adjust the idle. try that if its too low.

blue smoke huh? that doesn't sound too good

[raptor727]

blue smoke = burning oil, which could be either bad pistion ring or bad valve seal, and it doesnt smoke that much just occasionally. but i have tried the idle screw. could it be cause by the pcv valve sticking?