I was pulling about 4000#s last weekend cruising at 50 mph when I hit the go go pedal a bit to go up a hill the truck slowed about 10 mph no matter how far I put the pedal down. My egt s would climb from 850 to 1050 but my boost stayed at 10 psi. Fuel pressure would not go below 6 psi edge was on #2, no noticable smoke, air filter is clean, iat map and coolant sensors have all been changed and I have no codes. I know my problem is with low boost what could be the cause?

 

You probably have a leak. Make sure the connections are tight and there are no holes in the tube....

 

Sounds like a leak to me too, but could it be a bad wastegate diaphram????? Possibly???? Anybody think so???

 

From the air box I pressurized the intake system (40 psi) and plugged the side that goes onto the housing and I could not find any leaks. I put a new waste gate actuator on it about a year ago, and it still looks in good shape (no rust). I might try the turnbuckle thing on it since I can watch my boost now from the edge monitor

 

Clean the Map sensor, I read you have a K&N filter. Sometimes the filter oil covers the Map sensor with a film. The Map sensor in conjunction with other sensors control boost. This is a no cost troubleshoot.
MP

 

There are about 200 kms on the brand new map sensor and iat sensor