Oldsmobile/Buick Repair: auto, pontiac gran, rocker arms


Question
I don't know if you can help me or not, but there is no one else available, so I am taking a shot in the dark. My daughter has a 1996 Pontiac, Gran Am, 3.1L, Hydra-matic transmission. About 62,000 miles on it. All of a sudden it has a noise in it, like the old card trick with a bicycle, where the card is rubbing on the spokes when you ride it. This only happens when you let off the gas at say 45 mph, then when it drops down to 40 mph you here it. When you come back up in speed it goes away until you let off the gas again. It sounds like it is between the engine and the firewall. We can't find it, and in we , I mean a certified mechanic and me both looking. We have pulled the valve covers, it is not the rocker arms, altho it sounds like maybe a lifter rattle. We pulled the manifold and put a new gasket in it, not that. I don't know where to look next. This is driving me nuts....any ideas will be appreciated. Thanks.
Don.

Answer
Hi Don,
Sounds like the engine is rocking sideways,(actually foreward)due to the torque, and the exhaust pipe is touching the body or crossmember.
See if you can make it do it by placing the shift lever in low, accelerate to fairly high RPM's, then let off.
I have a 95 Cutlass that did the same thing...actually my son crossed an intersection hump too fast, and bent something a little. But there are some close fits under there.
Good luck,
Van