Quick Update:

I took a 30 mile round trip down the interstate at +/- 65mph this weekend while staring at my UltraGauge the entire time. It took forever to get to speed and briefly stalled while driving uphill. Although it seemed to work well while using cruise control. While driving both of my front O2 sensors seemed to be stuck at .460 volts and only fluctuated (+/-) .015 volts. The rear two were working normally.

I cleared out the trouble codes twice while driving and I got P0134 and P0154 codes after both clears. That痴 what is currently popping up now too.

I知 going to take everyone痴 advice. I値l swap out the connectors from a donor and give the NKT sensors a shot. Additionally, I値l probably strip the engine down to the block and put it all back together meticulously. I値l even go through the entire exhaust system and replace all the seals, gaskets, and studs. Looks like I figured out what I知 going to be doing this weekend.

This issue has been driving me crazy and hopefully this will be the end of it!

 

NTK 25623 - Upstream https://www.ebay.com/itm/143896963617 - I found them for cheap on eBay
NTK 25624 - Downstream https://amzn.to/3TomQmf - I haven't been able to find the downstream for cheap unfortunately

 

Word of caution about ebay: be careful of counterfeit parts. Some time ago I bought counterfeit NGK spark plugs off ebay. Only lasted 5000 mi, then bad misfires after the center electrodes wore away. Price was too good to be true, packaging and appearance was perfect. So I learned a lesson: buy important parts from suppliers that can be trusted, buy cheap parts from ebay that don't effect safety or reliability.