can pcm tuning cause this?
Thread Starter
Teching In
Joined: Jan 2010
Posts: 42
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can pcm tuning cause this? Long term fuel trims idle at 18 goes to 25 and stays. I have checked for all known problems several times. It throws lean codes. All I have left is pcm programing could this cause it. PSI harness and reprograming. 5.3 4l60 I drove the donor truck that everything came out of with no codes.
Thread Starter
Teching In
Joined: Jan 2010
Posts: 42
Likes: 0
Idle is 18 any rpm above idle goes to 25 both banks are the same. No vac or ex leaks. I have checked every thing changed fuel pumps and fpr, It threw no codes in donor truck. Short fuel trim is ok.
