Likely this issue. "T-SB-0124-11 September 6, 2011
Momentary RPM Decrease Above 40 MPH and/or
Reduced Engine Braking"
T-SB-0124-11
September 6, 2011
http://dl.dropbox.com/u/14313686/T-SB-0124-11.pdf
Momentary RPM Decrease Above 40 MPH and/orReduced Engine Braking
Service
Category...