well, here`s the results...it turned ou to be a bad tail lamp socket.apearantly, there was a small crack in it, thats why the problem wasn`t constant. i`ve put 200 miles on it and no problems

 

i had the same problem on my 03 , it would happen on startup and also intermittently going down the road. it finally stayed on , i found what i thought was a burnt out tail light. but what i found was that the base of the lamp was melted. wierd. i cleaned the contacts and bought a new lamp from wally world and have been fine since. i dont know why this occurred but my guess is that the lamps are poor quality.
hope this helps