i pulled this little bit of info off of this website...
http://www.intellidog.com/dieselmann/60bulletin.htm
i aready posted a this info but here it is again
2003-05 Various Running Problems, Check Engine Light; New EBP Sensor:
Trucks built before 1-17-05 that exhibit buck/jerk, hesitation, lack of power, stalling, stumble, black smoke, surging, rolling idle, changes in engine sound at idle or when driving at a steady speed, or with the trouble codes P2263 or P0299, may have an exhaust backpressure sensor signal that is incorrect or erratic. A revised EBP sensor is available if this is found to be the case. Part number 4C3Z-9J460-A. Broadcast Message 3815.
Normal EBP signal reading should reflect atmospheric pressure with the key on/ engine off. Typically, this is 14.7 PSI/0.88-0.9 volts at sea level, decreasing one PSI/0.10 volt for every 2000 feet of elevation. It should be within 0.5 PSI of BARO and MAP sensor pressure signals.