Fix Knocking noise on Impala
GM reports that it has isolated the cause of a knocking noise Impala that sounds like clanking or banging noise that comes from the rear of the vehicle. The noise occurs when you are stopping or parking. It happens most often when the gas tank is between half and completely full. You guessed it, the gas is sloshing against the sides of the tank and making the noise. So you have two choices, either put in a newly designed tank that has more baffles, or alter your gas level habits. The problem with installing the new tank is that, due to the redesign, you also have to reprogram the PCM. The new tank has different evap characteristics. The vehicles affected are: 2003-04 Buick Century and Regal, 2003-04 Chevrolet Impala and Monte Carlo, and 2004 Pontiac Grand Prix.
© 2012 Rick Muscoplat