My 2000 Chev. Blazer was getting 250 miles to a tank. I check it all the time - compulsive. Suddenly I am getting not even 200! It seems to be less with each tank even. The gauge seems to be fine until it hits the half tank mark, then it will suddenly drop and the rest of the tank is gone in one day. I only drive to and from work and a few errands - maybe 20-30 miles a day. This started to happen after moving almost 600 miles and pulling a U-Haul typle trailer - it's a 6 cyl. It ran hot during this trip -well it was June! It was well maintained - had a recent tune up and oil changed right before the trip. Could this be an electrical problem? Or what? I can't let this go on and I like the Blazer. Don't want to get rid of it.