I went flying in the evening. It's funny, as I didn't have the gas to fill the plane up last time I flew, so I put 5 gallons in the 10 gallon tank, flew for almost an hour and half, then put 5 gallons in the tank and it's still not full. I'm not sure, but I think it uses more 89 octane gas than it does 91 octane - I've been testing it.
I also need a new cylinder head temperature probe, as one is reading all over the place. I'll do that when I change the spark plugs, which should be in the next few engine hours.