What could cause a horrible surge at 3500 rpms, at wot. Already replaced fuel pumps, filter, mas, and 3 coils, nothing looks weird with a predator datalogging. and why would a speedo read 70 mph in park, and go up or down by pushing on the gas pedal. runs great, just a gremlin with the speedo. chris

 

Tune.

Take tune out of truck, see if that stops it.