surging 2001 7.3
Since the cooler weather has begun (KS) after the engine has started just fine (idling) you begin to hear the waste gate opening and closing sounding like a 'blow torch' (not cool for the neighbors @ 6 AM). One I touched the accelerator it was fine for a little bit, then the cycle would start again. Once driven it was fine.
Now with the OAT in the 20 degree range it does the above plus the engine & truck surges (approx 200 RPM). Not good.
A chat with a local dealer mechanic suggested I might want to replace the Exhaust Back Pressure sensor (4C3Z-9J460-A, retail $138.00), I bought one but decide to write you guys before I swapped them out. The mech explained this sensor reads the pressure between the engine and the turbo, and didn't really think the muff removal was a big factor. He also said he did some other work on a truck that did the cycling but didn't surge and the customer didn't complain about it (it's muff was removed). A buddy who had a '99 that he had removed the muff on cycled like this.
Help, my fellow 7.3 brothers. Not gonna do this much longer.


