I have a brand new neighbor that owns a 98. 5 4x4 long bed auto. The truck has 60K miles on it and he just started noticing that when he's driving down the road he sees the tach jump about 100 rpm's as though the transmission is slipping. He recently changed out the fuel filter and also added a Mag-Hytec deep dish cover. He didn't do the work himself. I've heard of this problem before. Advice or a pointer to a past thread would be helpful. The local dealership says they think it's the torque convertor or maybe some solenoids. Bottom line price tag is $3400. He's out of warranty. The truck looks like it has been well taken care of, exterior, interior and under the hood. All you auto gurus, please weigh in. He was cruising at 70 mph when the tach jumped from 2000 to 2100.
John
John