Went racing yesterday. Tried everything I could. My friend who sold me the radio was there, and we determined that the transmitter module needs to be repaired by Spektrum. The antenna is messed up. The original owner had rerouted the antenna so that it would exit through the top of the radio.
So since I wanted to race, I bought a $80 Sanwa MX-V. No more Spektrum questions (for now), and no more brown-outs, lawn-darts, or over jumps.