1986 cutlass supreme 307olds 5.0 v8.After driving the car for 20-30min its starts to make a tapping sound wen on drive(D) and pressing on the gas moving.But on park(P) and I rev it no tapping..when it does make the tapping sound the car runs rough and shift slow goin up and down.No smoke coming from the exhaust
-Just replaced the radiator had a leak.
help thanks

 

check the torque convertor bolts