5swapped3

Hey fellows swapped a 02 5.3 stand alone harness and stock tune pcm. It runs just not to shabby.

SYPMTOMS: backfiring, no power, hesitation, bad fuel mpg ( 3 gal to the mile).VERY erractic idle any where from 500- 3,200 rpm. ( Runs and backfires a lot worse when at operating temp.

Here's what I have done: New intake gasket, 8 new coils, new wires, new plugs, head gaskets, coolant temp switch, crank sensor, o2 sensors (upstream and downstream).

Parts I have swapped off my DD to see if it helps MAF sensor MAP sensor EVap sensor.
I traded a guy a transfer case for a whole upper intake minus the evap sensor. put whole upper intake on with my injectors not his with no change. Fuel pressure 58 psi at idle compression at 150 heads have been redone I have dopne leak test and still nothing. Although I did find that Bank 1 spark plugs are white as snow from running lean cylinders 2 and 4 running Perfect 6 and 8 flooding the gas to it. Only sensors I haven't replaced is cam pos and knock sensor any one have any other help. And tested injectors to.

raptorblackBird

I read about something like this before... this is just a stab in the dark: could you have the entire left and right sides of your electrical switched?


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D-Nuggs

This does sounds like a timing issue.