Weird Humming Noise
 

Hey guys,

For a little while now my car has been making a loud humming noise coming from the engine/transmission.
The car would randomly increase RPMs from idle to like 1300/1400 and would stay for a little. Then suddenly drop to like 300 or 400 then catch itself and shoot back up to 1300.
Half the time the car will shut off when it does this.
When this is not happening everythiung runs perfect.
But when the humming happens I have a loss of power and the car feels... Jumpy under acceleration.
Was told alternator :confused: and it was going out. So New alternator, belt and battery. Noise still happens. :(

I have a video of the incar when it happens:
http://www.youtube.com/watch?v=EbAhc...vDZr2FVJ38fFzQ
(Video was before new alternator, ect.)

Only engine mod is a K&N CAI, and I run 93.
I had put the factory intake back on and same thing happens, so its not that for sure.

Other facts: 131K miles, 5 Speed V8.

Any advice would be helpful.


Thanks, Kurt

vac leak? IAC?

I have also been told these.
I don't know if I had posteed ealier, but under acceleration the promble becomes less auidable, as I have found out. Which is where the vac issues came from.

More suggetions are welcome untill I find out what the cause is. Just incase anyone is wounder I will post the cause where it is fix.

Thanks for the help Steeda97.


(Just incase anyone is woundering, I will post the cause when it's fixed.)

Thats pretty much "text book" bad idle air control valve. Try pulling it off and clean it with some WD 40. Spray it out real good with WD and then install it back on with the WD 40 still inside the IAC. If this does'nt work, replace it. Good Luck!

Will do.
Thanks for your help!

Clean with WD-40???? :o/