ok, so my check engine light just came on. i took it to auto zone to have them check it and it came back with 2 codes.1) P0138= pcm determined the input voltage from o2 sensor 2 in bank 1 is to high for current operating conditions. and 2) Po455 large leak in the evap. ok now about that one he asked about the gas cap. that is a new gas cap cause i was getting that code before. i dont know how ot go about fixing these. i am low on money and cant really afford to go pay 80-100 bucks just for somone to tell me what is wrong. is there anything i can do to eliminate any possibilities? they printed somepossible causes but i do not know how to check them. if anyone thinks they can help let me know and i will type up what the possible causes are and send them to you. any help would be appreciated.

 

when it says 02 sensor is too high that means it crapped out and you need to change it. if not then the truck will see very bad gas mileage. also as far as the gas cap you need to turn it more than 3 times around after filling up. you need to hear that clicking noise to make sure it seals correctly