I got it welded up. Had a couple more leaks in that area than previously thought--you weld up one hole and it finds the next one and so forth. Finally got it all good to go. Pressure tested it on my bench with my air compressor. No bubbles anywhere along that crotch. I put it back in the truck last night (not an easy task getting it all lined up with the manifold!) but it was getting too late to throw the airbox, etc back on. I'll test tonight and report back.
Wished you lived close. I'd weld that up for you. Others have reported pretty good long-ish lasting results. If you can remove that section, a muffler shop will weld that up for you easily too.
The sensor extender won't "fix" it, just keep the sensor from measuring as much change in oxygen levels.No it’s not. I’m tempted to try a flange-style O2 sensor extender. If that fixes it, bad downstream cat. I’m curious if this one would work. Good chance the O2 sensor flange size is the same so I may try it.
Feature:Check engine light to fix M18 x 1.5 sensor vulnerabilityThe multi-part O2 sensor gasket for Toyota Tacoma tacoma and other models uses this flange form. This kit can be used in few different ways as shown in the picture above.With dedicated tools, perfect precision and repeatable...ucarpart.com
@harrydunn - did you need heat to get the nuts off when under the car? PB Blaster hasn't done anything for me. I need to get some Kano Kroil as it may have been my lucky charm on a terrible exhaust manifold job a few years back. I broke out my induction heater but it had a malfunction before turning the bolt red. I hate breaking out the torch in such a tight space.Popped the Y-pipe off. One of the nuts spun but I got it off. It boogered up the stud threads then the stud would not come out so I went ahead and took off the front exhaust manifold. Much easier to get the stud out when it’s on my bench (torch and ice method). Ordered a new stud, nut and 2 donut gaskets. I will see if I can put some welds down tomorrow and test for leaks.