New to the Forum. I have a 2005 Pony Express Motorhome on a C5500 Kodiak chassis with a 6.6 LLY Duramax and Allison trans bone stock with 46,000 mi. While driving, the CEL comes on and the engine loses power. The scanner reads a PO299, turbo underboost, that's the only code it shows. The engine won't rev over 2500rpm and barely make 50mph.I can erase the code while driving and the power comes back immediatley. There is no smoke from the exhaust.The CEL will come on randomly. It doesn't matter if its under load or cruising. Could it be a bad sensor? Most threads I've read guys had power adders causing the problem but this is stock.