Cm870 engine brake

[Lonestar10]

Exh sensor was done around October along with the open air baro sensor.. I diagnosed those with insite. Imap I can't get a straight answer and EGR dif has new tubes but sensor he cleans out he says. He's a stubborn ass from the if it ain't broke don't fix it era. I've told him several times things that should be periodically replaced. But he's drove truck for almost 50 years so what do I know.