okay....i have an 03 Mustang GT w/ BBK headers and cold air in-take

The CEL keeps comin on! ive had it checked a billion times and its say the 02 sensors. ive had them all 4 replaced and still no luck......im afraid to drive it far cuz of the CEL. sometimes it sounds like it dont wanna start but has never failed me yet....

here is wat the print out read from auto-zone...

The PCM has determined that a malfunction exists in the electrical circut for oxygen sensor 2 in the bank 2.
TROUBLESHOOTING P0156

im at my wits end....i replaced whats gets broken but only for them to break again and again...i need to fix whats actually wrong with the car so that im not fixin senseless stuff.

please help me....

 

Check for a vaccum leak. Possibly around the line going to the PCV valve. Could have intake gasket leaking also.

 

okay so imma be the typical female....
tell me how.....i dont wanna start poking around my car and break something thats not even broken....
How do i check for a vaccum leak??? Barney style! lol

please and thank you[8D]