Hello, been a while since I posted. My dad has a 2006 and it suddenly started to defuel. we have had this truck since new. Only mods are a boost gauge. I used to be able to get on it in 4th gear and above and the boost gauge would peg out at 30psi and pull hard. All of a sudden once I hit about 25psi the boost gauge drops to 0 and the engine falls on its face. If I hold the gas down it barely can maintain speed and RPM. if i completely let off the throttle, then roll back into it, it recovers and everything seems fine until i hit about 25psi again.

what broke? what sensor died, what do i need to change?

Thanks

 

Hmmmm..... 2006. Wasn't that the year of the plastic intercooler? I would check that as many have cracked in the past. Also, check along the path from the turbo to the intercooler, and intercooler to the intake manifold for deteriorated hoses.
Back to morning brew . . .

 

yeah i checked all these, Boost hold just fine until about 25psi, then it just falls to 0. If it was a small boost leak then It would still maintain boost, not suddenly fall