I am having a minor problem with my 05 F150 Lariat. Under light acceleration going up a slight grade the truck sometimes shudders (vibrates?). If I let off the gas or accelerate slightly it stops. At first I thought it was a feedback loop with the electronic throttle so I had the dealer reflash the computer but that didn't fix it. I've noticed that it happens right about the time the torque converter locks (looking at the tach) and I'm sure it has something to do with torque converter locking up and then disengaging continuously. Funny thing, it seems to happen frequently on the same hill at the same speed. Anyone else with a similar issue and what was done to fix it?