right now my truck has 175,000 miles and when i bought it had 140,000. i've replace the cps, icp, ipr, and hpop. a diesel shop told me to try the ipr and hpop when they found no codes. they said i had good oil pressure, good fuel pressure, and good boost. frustrated, i pulled the valve covers, and installed the clips on the uvch. they were a little loose, injectors are spitting oil. the truck runs way smoother, but i still have a unusually loud diesel knock when driving. very audible from inside the cab, drivers side. goes away when i'm coasting or idling. the idle drops down and then bounces back up to normal when clutch is engaged. the truck seems to run like it is cold all the time. the motor seems way louder all around than when i first got it, and still isn't running like it should. my truck doesn't seem to give codes. ? I was wondering if running my truck with loose uvch if that would mess up the idm or anything like that. I have a OTC monitor 4000 scanner and i get nothing. I use my truck for my business and would like to clear this up before spring when i need it everyday. any suggestions would help.