sitting at stoplight, idling smooth, occationally

it revs up 200 rpm then drops back to where it was

in a 3-5 second cycle

 

 

any ideas? going out to pull the codes now

Sounds like you have a vaccum leak to me, i'd check all of your vaccum lines, my honda did the exact same thing when i had a cracked vaccum line.

 

-Matt-

Might want to check the putor codes if you get bored. I thought someone once said that a bad connection on the the engine coolant temp sending unit can raise havoc. Could the air conditioning have anything to do with it? Don't think it was a Sube, but I remember a car that the idle would spike up just a bit before the AC compressor would kick in. Then the putor would again calculate out the correct idle speed. Just guessing for you.

Careful with those vacuum lines and plastic fittings. You remember! LOL

that thing always did that, even with the other motor. i think its the idle air controll valve sticking. b12 chemtool helps it go away for a while

thankie, i will try that