I am getting about 190 miles per tank on my 2005 GS. That is a little over 10 miles per gallon. Granted I tend to do some spirited driving at times, but I generally don't drive in rush hour traffic and spend a lot of time on the freeways. I always check my tire pressure, and I just had a tune up and replaced the air filter. Is this normal, or do you think this is something worth checking out? Thanks.