4.7. codes: P0457, P0456, P0306, P1128, P1129, P0364. 457 and 456 has to do with gas cap, 306 has to do with cylinder 6 misfiring but I changed it and the plug and still get that error. The other three codes...I don't know. Before yesterday, the truck would run for about 20 or so miles and then...