Emission codes 07 2.2 LS

[GrubbinGreg]

I have an 07 Ls with aftermarket exhast and intake. I bought the car like this already, I know the intake is K&N, exhaust is 2.5"or 3" I chacked out the codes I am getting and am mostly curious where to start.
P0496
P0171
P0442
P0455
From what I can find I should start at the gas cap, then purge solenoid, then o2 sensors. If anyone has input or knows if aftermarket parts would affect this let me know. I ran the car about 4,000 miles before getting these codes

 

[GrubbinGreg]

Still hoping to get sone feedback... only showing p0496 and p0171 after replacing gas cap and purge solenoid. I have seen other places it could be fuel tank pressure sensor or o2 sensors. After replacing the purge solenoid I ran without the check engine light for just over 80 miles, then when I turned my car on this morning the light was on again

 

[jeffsPSEMadness]

Also could be a dirty or faulty MAS air sensor I was getting the p0172 code to rich and was the mas air sensor was at fault. For the other check evap for cracked lines and filler neck for leaks and like you said the pressure switch.


Sent from my iPhone using Tapatalk