- Buick Ownership
I’ve noticed in my 16 regal gs AWD that I’m only getting 17mpg on average. I switched to running only 93, put a new air filter in, replaced and aligned all 4 tires as well. I plan on changing the spark plugs next weekend but I’m not sure why else my MPG is suffering. Any ideas? I have about 36,000 miles on it so far.