Morning all,

Went to take the son to school this morning. "30 degrees" Truck started fine and ran fine at idle. Pulled on the road and started out, once i get to a steady speed it acts like it is blowing off boost and and feels like someone threw out an anchor. I can hear a hiss, but if you give it more pedal it stops hissing and accelerates like normal. Once I stop accelerating and get to a steady speed again it will do the same thing over. Only happens in cold weather. The truck is a 97 F250 174000 miles. new fuel pump, and injectors 3000 miles ago at the stealership. Only other mod is a napa filter conversion. This same thing has happened in the past just didn't seem as pronounced as this morning. Other than the lag from I guess the lost boost it runs great as long as you are speeding up. Any ideas?????

 

Sounds like your EBPV (Exhaust Back Pressure Valve) is closing (as it is designed to do). You can unplug the electrical connection for it at the base of the turbo and it will not close. It is designed to close in cold weather to aid in warmup time. Most poeple just unplug it and can not really tell a difference. Hope this helps.

 

the plug for it is on the intake side of the turbo right under the orange hose. unplug it an no more hiss.