after my car has warmed up the idle fluxuates. it will rev up 2-300 rpm and go back to normal over and over again. as soon as it returns to normal it goes up 2-300 then back down and then up, and back down, ect. the needle never stops moving. the battery and alternator are fine as well as well as the vacuum hoses. what could be causing this?

it's a vacuum leak. Have you sprayed the lines down with carbcleaner to check for leaks? Used a vaccum pressure tester? Check your intake manifold & throttle body gaskets?

i got to get a moderator to delete some of these threads, its on here 5 times. my damn computer kept not doing anything so i didnt think it worked.

I believe that it is a vaccum leak also.

If it's not a vacuum leak try this...mine was doing that and I needed a new battery. I think the ecu was trying to compensate for not enough power to it. If you battery is fine then it is probably your egr valve. Let me know if those don't work

just got a new battery yesturday. i'll check for vacuum leaks. i just got a new engine put in so maybe something is loose. thanks