Recently, I had my timing cover gasket replaced under warranty for my 2018 CX-5 Grand touring. I had to have this done twice because the first time after I got it back, it sprayed oil all under the engine compartment and leaked again.The second time Mazda corporate got involved with my Mazda dealer and it seems that they have resolved the issue *knock on wood* and also replaced the hydraulic lifters. Having had a loaner now for a total of three weeks over the span of the two fixes, I noticed that the 2020 model that I was driving around was far more powerful and would stay around 2,000 RPMs going up a hill and still gain some speed or at least stay the same speed without having to downshift. My 2018 model has to downshift on even the slightest hill. It almost feels as if the car has less compression or that something is preventing it from riding smoothly.it seems when I go down the hill with the one I own comparative to the 2020 dealership model, mine stays the same speed or loses speed whereas the dealership cx-5 gains speed. I don't know where to start if it's a transmission issue or brakes rubbing. I don't smell anything or see anything that looks out of place as far as the brakes are concerned. Where should I start with this issue? Has anybody else had this kind of issue? Any advice would be appreciated.