My 3800 2000Impala pulses under accelloration. The engine doesn’t miss but if feels like something is alternately shutting off the fuel or perhaps letting raw air into the intake causing the engine to momentarily lose power. I have changed all plugs and wires, both ox sensors, fuel filters, and the fuel pump is putting out 45 lbs pressure. No codes show, not check engine light. The problem is noticably worse in wet weather but it is there in all weather. help!
If the wet weather makes it worse then you are almost certainly looking at an ignition problem. Coil/coil pack/distributor?