I need your ideas, please. 90 fd. 7.3 surging
 

Hi & thanks for looking & possibly your advice...90 ford 7.3 international 4x4 with overdrive, starts fine runs fine with the exception of fuel? or tranny malfunction? just crusing & @ no specific speed the engine rpm,s jump up for a few seconds & then resume to normal. this has no pattern & is intermittent & frequent. Has clean fuel, & new breather. Tranny speed sensor? if there is one & where? fuel pressure? I doubt it is the fuel because it happens @ 35mph & 65mph....Thanks!!!