Scumbag demandate #4

[Curtisj28]

2007 truck 2006 cm870. On my 4th typical scumbag "tune". Was done before I purchased the truck. Has a hx60w and all piping and valving has been removed. Has always had a rough idle and rough under power vibration. Pulling a pneumatic tank in Midwest grossing around 90k +-. Have been fairly steady around 5.8-6 mpg. Loaded both ways. I am desperately trying to get my motor to run smoother. But with said scumbag "tunes" we haven't been able to to do diagnostic tests thru insight. Tried injector cut out and it was kicking it out Everytime. I have just sent a message to uni about a ecm correction. But is there any other reason it would kick it out of Insight? (Local mechanic tried injector cut out)
I'm at my wit's end and don't know what else to do. And I'm tired of feeling like my motor is going to explode.