My 97 F350 Powerstroke has started to loose boost and blow raw fuel out the tail pipe at about 2200 RPM. When I get up to about 3000 RPM plus it seems to go away. But when I got down the through the RPMs it does it again. I've had two mechanics look at it but they aren't seeing a fall off in the boost. I replaced one bad injector but the rest seem to work fine. It seems like a computer problem or a sensor feeding data to the computer. Have you heard of this problem before?

 

if this problem is at cruise, it could be a pedestal problem. The turbo has a back pressure valve, and i have seen them close off the exhaust. When you step back into it it clears up. If no codes in PCM, head for a pedestal. The EBP is not serviced seperatly from the pedestal.

 

Thank you for your response. It happens during acceleration and acts as though it has lost boost until about 3000 RPM then turbo seens to kick in again. The mechanic had a boost valve on it to test and saw no fall off in the boost. Two diesel mechanics have thrown up their hands in frustration.