Code p 171 and 174 and P420 and 430 pulling both codes on each side. Catilytic converter and upstream O2 sensor replaced 15,000 Mike's ago on bank 1. What are the codes really saying?
thanks John

 

the codes (P0171 P0174) are telling you the engine is running lean on both banks . and the codes p0420 & p0430 are telling you that the previous two codes are causing imminent damage to your cat converters .
you need to stop driving the car !
its doing damage .
you need to find the reason for this lean condition . wether its an air/vacuum leak or pore fuel supply/pressure .
with the STR the most common air leak is the push connector on the intake elbow for the brake booster vacuum line .