I’m baaaack. Changed both gaskets, bought stainless nuts and cleared the codes. Tugged my camper 150 miles one way to Presque Isle without a hiccup. The evening I got there when I started it to go to the store, check engine light. Scanned codes and got an O2 sensor P0057 passenger downstream heater circuit low voltage. Made sure I wire brushed everything well before gaskets since I wanted to be sure just in case it grounded through the exhaust pipe. Long story short I put a new Denso in with the new included gasket and it runs like a top again.
Yeah I had a few people tell me my cat was plugged. It’s not. Never would have tugged a 6k+ pound, 30’ camper at 70 mph if it was. Don’t immediately assume a P0420 is a plugged cat.
Oh and by the way, the original P0420 was for the driver’s side so the gasket definitely fixed the original problem. When I changed the passenger side gasket I may have damaged the sensor when I lightly wire brushed the mounting base or it was about to fail anyway this triggering the P0057 code.
This continues to be a great site and a fantastic resource for repairs. I can’t guess how many $$$ I’ve saved on sites like this.
Glad you are enjoying the "learning experience" of these great vehicles. There is either a "panic" or just a "slightly ruffled" moment when on the road one of those pesky lights come on. If you have been "hands on" with your vehicle you immediately start processing the cause. If you don't have that knowledge of you truck you call AAA and have it towed. Then you always have this site as a place to ask, vent, complain and post your findings and fixes so we all learn from your experience. Iron sharpens iron... Thanks for the update... Chap