I have a Civic SI Guage Cluster and I noticed that the fuel guage needle doesn't seem to be dropping much every time I drive. I have driven over 140 miles and the needle is still more than 3/4 and a little less than full. It's weird. Normally, I would be close to half tank by 140 miles. Also, I tried moving the needle manually, but it went back to where it was. It just started happening. I doubt I'm getting 40 mpg-more like 29 mpg. I have an LS engine by the way. Any ideas?