Guy bought a used Lbz and doesn't know the history on the truck. Has efi, Fass 150(that was unplugged), factory fuel filter delete. Truck started throwing the P0090 so he began looking around nd noticed the Fass 150 was not hooked to hot, so he hooked it back up. At idle it clatters really loud( sounds like when u are testing the fuel pressure and increase the mm3 to 160 with ur laptop). He said the code will stay until he fills the truck up full and it will go away. Code will pop up if he goes more than 3/4 throttle.. What could I check for him?
