Hi Oppo!

So, I know it’s winter and I now have my winter tires on, so my fuel economy (of course) drops this time of year...however, I notice it’s been noticeably lower the last few months than it always used to be.

In the Spring/Summer I could often get 620km or so to a tank, and then around 580-600km in the colder Fall/Winter months. Lately though, I’m getting more like 530-550km in colder temps and 580km in warmer temps...that’s quite a drop!

I had slow leaks on 2 of my All Season tires that I had to constantly fill up during the warmer months, so that wouldn’t have helped, but I kept them topped up mostly, so I can’t think it would’ve affected the fuel economy that much...? I’ve checked the air filter and it’s not 100% clean, but it’s certainly not clogged at all, just a bit dingy. I also took out and cleaned my car’s MAP sensor in case it was dirty and not reading correctly...that made no difference either. One of my wheel bearings went in the summer so that could’ve also contributed, but it’s replaced now, so no more drag from that...

Can anybody think of another reason I am overlooking other than brakes dragging or some such? I don’t seem to feel the brakes dragging or the like and when I had my winters swapped on / my last oil change done, the mechanic didn’t notice any extra drag on the wheels from sticking brakes or anything...?

It’s a bit puzzling! Cheers! :)