I am one of the ones that went from Diesel back to Gas...
First diesel was a 2004.5 Silverado with the LLY Duramax. Had no issues with that just wished at that time it had the 6spd Allison instead of the 5spd. 2018 I sold it and bought a new 2018 L5P Duramax SLT/Z71 CC. Had a ton of issues with it but it towed great and over the life of it at 84K miles averaged 16.7 mpg. Straight freeway driving was 18-20, to work and back was 16-19, around town about 14.
That truck got lemon lawed and when all said and done, I ordered a 2024 GMC 2500 AT4 with the 6.6 Gas. I was tired of the emissions crap, the cost of diesel, the fuel filters, DEF and just all the electronics required to run the new Diesels.
I have 5,000 miles on my new truck, and I love it. It tows just as well as my diesel, but I do miss one thing...the Exhaust brake.
I just did 965-mile round trip towing my Can Am in my 16' box trailer to Utah and back and I averaged 9 mpg, but my buddy's I was following all wanted to do 85-90 mph! UGH!
Had I stayed where I like to tow....65, I would have been in the 10's for sure. That trip in my Duramax probably would have been 12-13.
So far in the gasser, freeway driving can see 19 mpg, but it is usually around 17-18 at 65-70 mph.
To work and back 15-18, around town about 12-14.
I simplified my life going with the gas version, but I do miss the diesel just a little bit...only for knowing I could tow whatever I wanted pretty much. Now having said that, I won't ever get a trailer that is that heavy...so for me going gas just made sense and I love it.
~Dale