i own a 2005 f150 fx4 supercrew. a few months ago while driving in the city i noticed that the rpms reved around 2000, then went back down, when stopping at a stop sign, then going. this also happened when i was entering the freeway on the on ramp. at approximately 50-55 mph the truck jerked twice, but once passed the 55 mph mark the jerk went away but the rpms were really high, around 2000, then went back down. today when i got out of work i put the truck in reverse to get out of parking stall and then went into drive. once the truck started to moved forward it stuttered a bit, felt if i was in sand. after that it drove normal. while going home the rpms were high again at the stops, then back down. have already added fluid.