1999 GMC Sierra 2500 SLE 8 Cyl 6.0L
What would cause a whistling sound under acceleration?
Engine makes whistling sound when I accelerate or push on gas when in park. Does not do it when cold. No warning lights are on. It started a couple of weeks ago when pulling a trailer.
Vacuum leak. there is no substitute for you listening and locating the origin of the noise with your ears while making the noise happen over and over. You will have to climb up there and get close to the top of the engine with it running, carefully obviously. You can manually move the throttle and listen and look.