I have a 2001 GMC with JBA headers , AEM intake, 3in flowmaster. recently i've my truck starting pinging at different times when driving more noticed when pulling a trailer.
Around the same time my gas gauge has gone whacked, the low fuel level light has be coming on when i still a half tank left so when i stop fill the tank, start it back up again the stays on empty till after driving a while then it jumps to full and then back again.

so what i'm try to saying is if my gauge or my fuel pump is starting to go out,would or could this be why truck has starting pinging ?

 

pump could be bad and your fuel level sensor is bad

 

so if this is true so would this still make it ping under load ? when i checked the plugs they looked a little on the lean side, so if it's not getting normal fuel pressure because the pump is stating to go bad, could this be the reason ?