I mean, they should behave the same... right? It's a CAR!! Not a fickle person! Yet, my experience with my car has been that there are those times when it feels more responsive, the engine more eager to rev, the steering wheel more eager to turn (less stiff) and feels like it handles better. Then, there are those days when it feels less responsive, more sluggish, the steering wheel feels harder to turn, feels like it doesn't want to handle... Thankfully, these days, I am getting more of the former behavior and fewer days where it behaves like the latter. When I first got the car, it was the other way around and I was deeply unhappy feeling that I had made the wrong purchase decision. The car is a 2007 Corolla CE 4SPD automatic, with 65K miles. I'm using 0W20 Toyota. I can't put my finger on it... I can't say that its' correlated with the weather. The best predictor of good behavior is when I use the local full service Mobil Gas station. Thus, I always go there, but even then, I get the occasional "bad" day. Is this normal? Am I crazy? Chime in, pls.