1998 Chevrolet 3500 Pickup Q&A
1998 Chevrolet 3500 Pickup Question: Why dose my 98 k3500 seem to miss when I get up to cruising speed 50-60 mph?
Gas or Diesel engine sounds like you might have a injector acting up. Maybe just dirty try a good injector cleaner and a tank of premium fuel first. Also get it scanned for codes there may be one that is pending and hasn't set yet. - torque wrench