Scotty, I have a 2012 GMC Acadia FWD with 107K miles on it. Over the last three or four months, I have noticed more and more lag time in acceleration, and sometimes the RPMs near 4,000 before I feel it shift gears on a moderately fast take off. I knew when I bought it in 2017 that lighter GM vehicles can develop timing chain and/or transmission issues after 100K miles, so wisely (or unwisely), I purchased a 3-year powertrain warranty on it. The 3 years is up in December 2021, and I have a checkup scheduled in April 2021. Wondering what your first best guess is as to what may be causing the sluggish acceleration and higher rev--- any thoughts? I want to walk into the dealership with at least one possible idea, in case they try to throw something my way that isn't covered in the warranty.

As an aside, I know GM's poor track record with automatic transmissions on SUVs and light duty trucks. Why did I buy it? My last vehicle was totaled in 2017, and I wanted to replace it as quickly as possible. Dad was a 30-year employee of GM, and he found the Acadia for me through connections with a sales manager friend; so it was a gratitude buy. I had my eyes set on a Sierra 2500HD (care more about durability than gas mileage), but opted for the Acadia. If it's on it's deathbed, I'll start shopping heavier duty V8 trucks again).

Thanks.