I haven't given much thought to gas quality and I'm still getting to know this truck, however lately I have been giving a lot of thought to gas mileage.
I'm not much of a number cruncher and I haven't been very diligent with tracking my KM's to Litres. However I know that I usually get around 425ish KM on a tank, and that's with about 12 litres left.
Lately I've been filling at Costco because it's close and usually about 5 cents cheaper. After my most recent fill, I noticed my MPG was suddenly very poor and I had to re-fill before 350km. On suspicious of gas, I filled at Shell and I'm now on track for one of my best ever mpg/tanks.
Highly anecdotal at best. But a little googling seems to suggest that Costco gas especially the winter formula has lots of ethanol and can be a cause of poor gas mileage.
I'm assuming Costco must have recently switched over to a winter formula? Anyone else notice a sudden big difference in their gas?
I did recently have a o2 sensor replaced, but the extreme drop was a few fills after.