Please Help '08 GMC Sierra 2500 HD, knock/fuel problem?
 

Hello,
I have an 08 GMC 2500HD w/ 87k miles and its running rough. Anyone every have any of these issues, or know what it maybe? Someone suggested pull the fuel injectors and getting them tested? Thanks in advance


GOT TRUCK STARTED AND ENGINE KNOCK PRESENT
DIAGNOSED INJECTORS AND 6 OF 8 INJECTORS SEEM TO HAVE EXCESSIVE BLEED OFF
ONLY ENGINE CODE PRESENT IS U0101
NO FUEL FAULTS

This is what I've done so far;
DRAINED FUEL TANK
REPLACED SENDER
PURGED FUEL SYSTEM
REPLACED FUEL FILTER
PRIMED SYSTEM
CLEARED CODES

Are you sure the fault code was U0101? Could it have been P0101? If it was indeed P0101 you have a defective mass airflow sensor, or something similar causing this fault code. Did you perform or have someone else perform an injector contribution test to see if the injectors are working correctly?

That’s the only code that popped up U0101, but I don’t think it the transmission control module.