Help! My truck operates in two different modes. The first one: Engine has more vibration; Accelerator has a heavy feel to it; Takes longer for the engine to get to the "sweet spot"; Overall it feels lower on power. The second mode: This has a light "pedal feel"; Engine reaches the "sweet spot" quickly; Gears(6 spd. ) shift smoother; Runs like a "scalded a** ape"! I would appreciate any help someone could give me. This is really annoying!