Hey all - long time reader of the forum but first time post for help
I have a 2006 SR5 4WD V8 with 185k miles. Car was SoCal and CO owned, so the undercarriage is in great shape, and I've been meticulous about maintenance, etc since my ownership from 150k three years ago.
In the past year I've noticed a ticking noise, which I'm nearly 100% certain is the passenger exhaust manifold crack, get louder and louder over time. At first it didn't bother me as I would turn up the stereo and move on with my day. However, I am now having DTCs come up, as well as the VSC OFF, Traction Control, ABS, VSC TRAC, and CEL lights all show up simultaneously, which annoys me to no end.
Fix try #1 - I've bought a bluetooth OBDII scanner and cleared the codes when they come up (first couple months of DTCs). The codes/lights would go away for a few hundred miles but eventually come back up. Original codes were P0420, P0430, and P0504.
Fix try #2 - Add Dorman spark plug fouler spacer to bank 2 rear O2 sensor as this is what most 4th gen V8 owners on this forum suggested to try to "trick" the secondary O2 sensor from pulling the codes. DTCs P0156 heated oxygen sensor 2, bank 2 - circuit malfunction and P0420 came back shortly thereafter.
Fix try #3 - replace bank 2 O2 sensor with new DENSO O2 sensor ($50) along with Dorman spark plug fouler spacer. P0420 code returned
What next? I haven't replaced the rear bank 1 O2 sensor but added the spacer, like I did on bank 2, but wondering if that will even fix the DTCs or if it's something else. More than likely, I'm just ignoring the true culprit - cracked exhaust manifold - because I don't want to spend $2,000, but hoping you can help me definitively find a fix.
I'm trying to drive this car as long as possible and at 185k with recent timing belt and other extensive services, feel like a goal of six or more years at 10k miles/year is possible. But, the lights are driving me CRAZY!
I've added some screenshots of the previous trouble codes as well as catalytic converter temperatures, fuel trims, wide range equivalence ratios/voltages in case that helps. If I should look at any other areas of the OBDII scanner for values that could help track down the issue, let me know.
If it is the manifold, I live in an area where no emissions are required for registration and would be open to doing long tube headers and keeping secondary cats as to keep the repair costs as low as possible. However, If I should just run LT headers and remove secondary cats (if possible), I'm open to that too, so long as it doesn't bring the codes back.
Beyond the exhaust tick and codes/lights, truck runs perfect. A little sanity check, please?