I HAVE A 02 TAHOE AND MY CHECK ENGINE LIGHT IS ON. THE CODES THAT I PULLED UP ARE 0171,0174 BOTH BANKS TOO LEAN ALSO CODES 0440 EVAP SYS MALFUNCTION AND CODE 0452 EVAP SYSTEM PRESSUER SENSOR LOW. I HAVE NO IDEA WHAT TO DO FIRST OR WHAT TO CHECK FIRST. IF ANYONE COULD GIVE ME SOME IDEAS OF WHAT COULD BE THE PROBLEM OR PROBLEMS I WOULD GLADLY BE THANK FULL.NEED HELP!!!!:crying:

I HAVE A 02 TAHOE AND MY CHECK ENGINE LIGHT IS ON. THE CODES THAT I PULLED UP ARE 0171,0174 BOTH BANKS TOO LEAN ALSO CODES 0440 EVAP SYS MALFUNCTION AND CODE 0452 EVAP SYSTEM PRESSUER SENSOR LOW. I HAVE NO IDEA WHAT TO DO FIRST OR WHAT TO CHECK FIRST. IF ANYONE COULD GIVE ME SOME IDEAS OF WHAT COULD BE THE PROBLEM OR PROBLEMS I WOULD GLADLY BE THANK FULL.NEED HELP!!!!:crying:

fuel pressure checks first....both banks lean.....usually random miss fires follow if the fuel pressure falls below 53psi....

60 psi is the correct pressure....