hello all
i need your help to figure out why my car have negative fuel trim, my car is new model 2016 Tahoe ls z71 stock car 17000km only, i bought hp-tuners to tune it because i was lossing gas mileage !!!! and having rough idle!!!!
first time i did data-logging for it, i find out that the car have negative long fuel trims (bank1 -9% bank2 -7% in idle at 550rpm):bigshock , and 2 to 4 degree knock retard at 1800rpm to 2100rpm i attached the log file
i was thinking that i have dirty or clogged fuel injector but negative fuel trim
so any suggestion on how to address the issue with my car ???
:run 1.hpl ,