Keenan
Newbie
I bought a 1998 z71.5.7, 265k miles, a few months ago, and am in the process of restoring it to a respectable level. When I bought it, the cats were deleted and had the loudest muffler known to man. Long story short, I added the cats and changed the exhaust. With a drastic noise reduction I noticed this issue: When on the highway at say 65mph and I let off the gas, I hear a rumble noise, almost like a tran brake. It is there until the truck down shifts and then goes away. It only occures at highway speeds when decelerating, not accelerating and not around town at lower speeds. Any tips or direction to solve the issue is grealy appreciated.