i just bought this 05 srt4 a week ago with 40k on it and im having some problems with it... 3 days ago i pushed the gas all the way down and only got to 4psi then threw a code p0420 --catalyst efficiency low bank 1-- the car still wont go past 4 psi and now its starting to bog out pass 3k rpm. its also just started throwing 2 more codes p0171 --fuel system lean-- and p1188 --tip sensor performance-- i dont know much about these cars but from what i can tell the only mod on the car is an aftermarket down pipe with an electronic cut out thats not wired and a aftermarket boost gauge. need some helpppp

 

bad O2 sensor maybe? also make sure the tip sensor is hooked up 05s are sensitive about the tip sensor and the car is probably in a safe/limp mode so its only allowing 4psi, that would be my assumption since it has a lean fuel code