idle issue anyone got any ideas

[bass.tony68]

ok so my 93 240sx has been having this idle problem lately. it doesnt happen all the time just seems to happen randomly. im driving along and when i go into neutral and coasting the RPM drop all the way down to like 250 then rattles and shoots back up to like 1500 and causes the belts to squeak and it keep doing that for a bit then goes back to normal. any one got any ideas what could the cause of that be and how would i fix that?

[ultimateirving]

ok so my 93 240sx has been having this idle problem lately. it doesnt happen all the time just seems to happen randomly. im driving along and when i go into neutral and coasting the RPM drop all the way down to like 250 then rattles and shoots back up to like 1500 and causes the belts to squeak and it keep doing that for a bit then goes back to normal. any one got any ideas what could the cause of that be and how would i fix that?

IACV is sticking and its trying to catch itself when the idles drops down, my car also does this with the a/c on.

[bass.tony68]

do you know how i can fix that?

[ultimateirving]

take off iacv spray with some carb cleaner or similar, then maybe an engine safe lubricant to get it moving again. Not sure what lubricant to use. see if anyone else has posted a thread on whats safe to use in there. (ive sprayed in some WD40 but dont think thats really a good idea.)