P0300 GMC 2002 1500 Sierra 4.8L V8

Question

I have been dealing with a P0300 code that keeps coming back.  Have replaced the plugs, measured all fuel injectors (11.9 ohms each), then replaced the crank position sensor...and still the code comes back.  No other codes come up, and the thing is there is NO NOTICEABLE LOSS OF PERFORMANCE, IDLE, STARTUP...all is fine.  The truck is a late '03 build and only has 64k miles.  Before I start wasting more time and money chasing this ghost, any suggestions??

Answer 1

Remove the upstream 02 sensor , and leave to the side, you would need to connect the 02 sensor as it hangs outside safely out of the way there run the vehicle and see if the misfire returns what you will be looking for is a plugged exhaust system,  check for  a pending code for a misfire condition