blackbird-ls1

iTrader: (3)

I have this p0300 intermittently usually when not under a load. The 6.0 liter motor runs smooth with no signs of a missfire or running rough at all! It's a my 2002 2500hd 4x4. I have replaced the knock sensors, plugs and wires, and fixed a exhaust flange gasket leak. I was on occasion get lean bank 1 and two codes. I sprayed the intake and vacuum hoses for leaks with starting fluid and nothing. I checked the coils with soapy water and nothing. I cleaned the maf sensor with maf cleaner and went back to the original air cleaner assembly and removed the K&N fipk thinking it was causing the lean codes. The only other thing I think it maybe is the crank position sensor is bad or maybe the O2 sensors are. Any help would be appreciated as this has me highly frustrated. Thanks!

Velle72

What about your fuel injectors bro maybe check the screens inside of them see if there's any foreign material. Be nice to check to what cylinder is misfiring if there was one with a GM T echII.( dealership scanner)

1FastBrick

iTrader: (16)

I would pull the Intake manifold. If the rubber is smashed nearly flat with the plastic, Replace them with the updated design.

They will leak on the bottom side and you won't be able to detect it.

JMD759

iTrader: (6)

The intake manifold gaskets are very common, may not be your issue but definitely a place to look. The upgraded gaskets are much beefier and are worth the extra money. Mine were not detected by regular methods of testing (propane, spraying ect.)

blackbird-ls1

iTrader: (3)

Thanks, I will check both. I know the intake gaskets looked questionable when I replaced the knock sensors. But I am going to sell the truck once it's fixed and did not want to change the intake gaskets.I will try and see if I figure out what cylinder is misfiring. I bought a better scanner and I think it shows the cylinders firing. I appreciate the help!!!
Thanks!