if its on the tv, how long are you leaving it? mine randomly chaanges between displaying from post, to sometimes not displaying anything till login screen
could have been a few things
Something coming unseated slightly
Momentary short when bumped in the car
CMOS battery almost dead (Taken out the house, low temp car ride drops the voltage a tad more so loses some/all settings, back in the warm voltage creeps up and holds settings again).