This is my first post, first swap, first attempt at tuning. I have a 2001 5.3 LM7 with a 02 Z06 cam, 799 heads, L33 rotating assembly, stock truck intake and throttle body with 25317628 injectors, Walbro 255, modified factory harness swapped into a 79 cutlass.
The car will start and runs great until it gets warm, then it starts missing badly throwing a P0300 code. Any ideas of what this could be? I have the current HPT as well as the HPL file attached.
Replace both the upstream O2s, only GM/NTK/Denso.
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Thanks for the reply.
They are both new denso's white plug. Could it be the wiring or maybe where they are located in the stream?
Swap them side for side and see if the weirdness follows the sensor, or stays on the same bank.
Does 'denso white plugs' translate to an actual part number? Are they the correct sensors for the tune file, 2001 Sierra 1500 5.3L?
Good point, no it doesn't really translate. You have sent me down the right path, the harness I used had white connectors for the isolated sensors and it looks like the 2001 Sierra would have had the 4-wire case ground sensors. Unless the PCM can use either or depending on the harness? ThanksOriginally Posted by blindsquirrel
Thanks to blindsquirrel, after changing the harness plugs to the 4 wire flat plug, and putting the correct injectors for the 2001 GMC, the car runs good after warm up. Now I just need to start adjusting the tune.
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