Hey guys i was looking around the site and ran across a problem another guy has that i have from time to time and was wondering if anyone had a clue. On my 4.6L supercrew when its cold out and you turn the heater on i get this god awful vaccum noise that sounds like a goose being strangled! the engine idles up and want to lurch forward a bit if your at a stop light. if you give it some gas it goes away. i have also noticed it doing it when i let off the brakes to leave a light it will do it, it seems like if you use any thing that uses vaccum it acts up. any ideas?

 

Is it a "hooting" noise? If so, sounds like the iac valve is fluttering. I assume you have it in defrost mode when turning on the heat which actuates the a/c compressor causing the engine to idle up. This is why it coincides with the heat. Try tapping on the valve when it happens.

 

thx hubuscapus for posting this in here, didnt think about it, but bigbronc is right, it is the IAC valve, I did quite a bit of researching and got the same answer, flippin IAC valve, same noise, same idle jolt...so yea, Im just gonna take mine to the factory, cuz i dont feel like fiddling with it...