Wes,
Had this happen to my 2002 ext cab GMC. Went to take off from the house after ashort warm up period, and when I put it in gear no gas pedal. Had to shut it off and restart. Ta dah, it was miraculously fixed. Haven had it happen again since (25,000 miles or so)
I did have one instance in my 03 where I was coming down an on ramp to the highway, kicked it into passing gear and had only engine response (engine reved up to about 45-4700 r's) ,but no forward motion. Had to release the pedal and press it again, but a little slower this time and all was well. Had the dealership check the trans on the computer which of course found no faults.Haven't had any recuring problems since then, no matter how hard it's driven.