I had mine do a slow acceleration after backing out of driveway, then hard shift and it felt like it was in the wrong gear. Strange, looked down at guages and turned around to my house, about two blocks total. Now that I think about it I can't remember if I was actually getting CEL....I have a scanner so I checked it and did have a code, can't remember what it was now, after I cleared the code it was fine for some time. It did it a few more times and so I ordered the ignition switch from my googeling. I also had my door is open and key is in the ignition beep happen when I turned left sometimes, but intermittantly. I kept the ignition switch in the back of truck for 3-4 months before it did either symptom again, at which point I took the time to change the switch.
How long have you had the truck? I ask because the reason the ignition switch fails commonly is people and their huge key collections pull on the tumbler cylinder and cause problems. The transmission cares what the gear selector and the ignition are doing and if either one of them give an odd signal the trans will go into limp mode which as strange is it is, is hard shifts....so that the clutches get enough pressure to engage while you limp the sucker home.
I would suggest an OBD scanner.
Are there any other non-related quirks with the truck?