Has anybody ever tried any of the Plug & Play performance chips that plug in under the dash? They claim that it does not void your warranty and is undetectable if unplugged before you go back to the dealer. They also claim up to 60 more HP & 4-6 MPG. What are your thoughts and has any of you heard of anyone using any of these? Thanks

Here's one that keeps popping up on my computer.

https://performancechiptuning.com/products/chevrolet-performance-chip

For what purpose?

those are Junk. Superchips or bullydog are a few i would trust. Dont expect a ton of power gains unless your a diesel, but they will firm up transmission shifts and add a little horsepower.

MPG. I'm hoping for the improved gas mileage. I averaging 16MPG now but would love to see higher MPG if possible. I don't need more HP but it wouldn't hurt if I could get both. It would be going on my new 2026 Chevy 2500HD 6.6 gas engine. Thanks

Everything I've read or seen says roughly 1 to 3 mpg better. That's not a lot for what a tune costs. I believe clean oil and fluids clean air filters, proper air pressure in tires, and good driving habits is best. That's just my opinion. Enjoy your new truck.

Take before and after vids.

You may never have a better chance for
all the electronic junk to be working properly.
(While it's new) I say go for it.

If mine I'd be studying the diagnostics
like a hawk. And steady diet of fluid film.

They are good (bullydog) and bad like everything else. There are ones that just plug in and are set and ones that plug in you can change modes on. My buddy had one and like running his truck in race car mode all the time. He thought it was just the mileage as to why his head warped and he had to have it machined. I suspect race car mode. I might get one, I'm not saying they are bad, but you have to watch it too.