2003 Mazda 6 3.0L ATX CEL's

[rdo1953]

Original owner w/97K Mazda 6S V-6 ATX w/reman motor since Nov.09 91K. AER motor w/rebuilt Jacto tranny+CV joints. New Weapon X coils, new PCV valve, new NGK Iridum plugs, CP-E CAI w/customizer, new CP-E headers+Cats, Fluidampr, oil+tranny coolers, CP-E stage 1 trans kit, AWR comp. radiator, new Amzoil 5-20, new Amzoil tranny fluid, new coolant and thermostat, TB coolant bypass, Magnaflow resonator, MazdaSpeed cat back exhaust. DashHawk. New OEM bank 1 (pre-cats) O2 sensors-bank 2 (post-cats)new in box not yet installed. Car runs ok. But it constanty throws P0139 (O2 sensor circuit slow reponse BK1, S2),P0431 (warm-up catalst effientcey below threshold B2). These codes are thrown in standard auto tranny mode around town driving. Has also thrown P0140 (O2 sensor no activity B1,S2), P0153 (O2 sensor slow response B2,S1). When I use manual shift mode and run rpm to 3-4K car will throw P0300 (random misfire). Going to check alternator output, fuel pump pressure. My mechanic has checked and double checked everything but has missed something. Cleaned fuse box. Cleaned MAS. Tried Nautilus resistors for bank 2-no change. Cold start will get mild exhaust smell in cockpit. EGR? Any help would be appreciated.

 

[Blendercloud]

You may want to check the wiring and plugs going to your O2 sensor.

 

[The Great NY]

u have headers. thats why your throwing the CEL for the O2's. go to www.o2simulator.com and pick up a dual output o2 simulator(universal) and install it. and you should be good with the O2 sensor CEL's


for the misfires, look at the Mafci connections, and plugs. and also, get some maf cleaner and clean your maf. a dirty maf will/can cause random misfires too.