7.3 turbo diesel

if it were me.. and that's only conjecture, mind you...I think I would be asking the mfrs of "bullydog" about it.. not this group.

I DO think we can rule out the cold air intake.

Hope that helps.

and anuvver fing....

I can see two possibilities for the "flutter.... first may be because of the lack of sound deadening in the intake caused by the addition of the cold air system.... Incidentally, most of the so called cold air systems I have seen for the 7.3 wind up drawing more hot, underhood air than the stock system they replaced. A much better choice for an intake might have been the AIS available at most Ford dealers. This sytem still draws air from behind the grille but uses a filter medium just like the 6.0.

For the backpressure codes... there are several different codes that deal with the EBP and the EBV... I am not going to try and guess which. Most common is the P0470 (memory thing) and similar and usually refer to a failed or plugged EBP sensor and/or a plugged EBP pipe. Other possibilities include a disconnected EBV actuator in the turbo pedestal (possibly disconnected when the exhaust was installed....).

You're welcome....