TRUCK IDELS UP AND DOWN IN PARK OR DRIVE. ACCERLERATES UP ON ITS OWN EVEN WHEN WARM.MAKES A LOUD WINEING NOISE LIKE TWO MALE CATS FIGHTING.REMOVED BELTS FROM TRUCK STILL MAKES THE NOISE.IT SOUNDS LIKE THE NOISE IS COMING FROM THE UPPER MANIFOLD NEAR THE LOCATION OF DISTRIBUTER. COULD THIS NOISE BE PART OF THE FUEL INJECTION SYSTEM? OR IS THERE A VACUM PROBLEM UNDER THE UPPER MANIFOLD?
Chevrolet Q&AAsk Your Question
1996 Chevrolet Suburban 2500 Question: WHATS IS CAUSING THIS LOUD VACUM LIKE NOISE?
Answer #1ZeeTech February 13, 2011, 18:03Master
It's probably a vacuum leak. It can be traced down with a smoke pump. It will inject a thick smoke into the intake and makes leaks visible.
Answer #2techlund1 from Cottman Transmission and Total Auto Care, February 15, 2011, 08:24Technician
Sounds like a vacuum leak a smoke test would find this