Since I have moved to Tampa FL I do alot of driving on I-75 and I-275. I have noticed that if I drive about 62 to 65 at about 1900 rpms I get around 20 MPG. But yesterday I went to Ocala FL and I was in a hurry and I drove about 75 at 2300 RPMs. I burned alot more fuel than a normally do. I have noticed to according to my gps that my spedo is about 5 mph of slower than I am going. Does any else notice this. I plan on removing my muffler soon to see if this helps. I would love to get a gear vendor over drive because at 70 I am about 2300 rpms and I would love to turn about 1800 rpms at that speed and I think I would have enough torque for 1800 rpms at 60mph.