Under load engine will misfire especially hard up hills. Ill have to hit pedal hard till it will get the power needed to get up a hill. Will stutter on flat ground as well just not as severe. Unless I get really touchy with the pedal will it be normal on flat ground.

Installed new air filter.
Cleaned MAS
Cleaned throttle body
New Coil packs
New spark plugs
New knock sensors (new harness too)
Installed felpro gasket
New fuel pump
Tested wires and they are all good .975 average on multimeter
installed new magna cats and a exhaust
Instead new o2 and oxygen sensors too

It throws the P300 code and the codes on the knock sensors at the same time. Any thoughts on what I should check? Have been browsing posts going back to 2005 still cant find the answer. Thank you for any comments

 

 

might it have a high octane tune on it and you are running it on regular?

 

Did you do a crank relearn after those repairs?

 

interesting comment. I dont belive there was ever any modifications done of the vehicle. All the lights were just about dead and needed replaced when purchased as well as all mechanical needed cleaning fixing. With each upgrade I can feel the engine getting stronger. I will be upgrading the wires tonight. It is possible they are shorting with the new spark plugs and coils. Il update tonight

 

I recently found about this, Ill be installing new spark plug wires tonight. See how that goes. Even if everything would work should I still get that done?

 

If knock sensors were just installed & you are getting knock sensor codes- I would be willing to bet your new knock sensors are bad and/or the harness which should have been replaced when you did the two sensors. Clear the codes, if within a drive cycle the knock sensor (P0332 / P0327 - and/or) codes come back and you have no apparent knocking - new ones are most likely culprit, torque is approx 15#. There are tons of posts on defective knock sensors & the stories of "do-overs" common. The "bolt section" can also separate from the "nut" section when you screw or unscrew them in position - this can happen even when torque value observed according to many posts (when you look at construction of the knock sensor you will see "divots" to keep the two sections from "spinning".. NAPA makes a great knock sensor ECH DKS238, google "bad knock sensors GM forum" Good luck, but I am guessing this may help....
Ohm readings you can check on the harness each pin to ground is approx 101 ohms +/- ... but just because they pass that, doesn't mean they will pass the "knock" (where they create voltage) test....
Read up - hopefully this helps.... "GM 6.0 knock sensors defective" - just google that, much more info on the net in that search than on this Hummer forum....those sensors were used in a bunch of different GM vehicles/engines... unfortunately they are under the intake.....You also mentioned a P0300 for a misfire- IF you have "knock" from that, ignore above, as the sensors may be reacting to an actual event... however if no knock is observed, this may help...... but again just google GM 6.0 - lots of info out there

 

Appreciate the detailed response. I did use a new harness forget the manufactor but was all highly reviewed all oem parts from stores so no counterfeit parts installed. Will keep in touch. Determined to crack this code.

 

Bulletin No.: 16-NA-383

 

great post, Im going to get a few cans of liquid moli. The new spark plugs that came in were not up to spec. They were reading all .450ohms. The first pair I ordered online were counterfeit. I can only imagine how dirty they must be. Im going to go for drive tonight.