Which AM/Bama tune is more fuel efficient? I just got my tuner last week and so far I've noticed that my MPGs have gone down. Before I was filling up every 5 days and the past 2 times I've filled up I've had to do it in 4 days. I drive at the speed limits, so I usually don't get past 3,000 RPMs. So far I've used the 91 Street and 91 Race tunes and I've noticed that the RPMs go higher than usual with those two tunes. Can this be the reason? Should I switch to the 91 Performance tune?