Most recommendations I have read at a Duramax Forum say to remove the chip and return to stock and see if the problem persists. If it does then it isn't chip related and should be investigated. If it goes away, then you have the culprit.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof