Hello; I am new to the forum, I have recently purchased a 2007 Ram 1500 with a 5.7 Hemi. I went from a 17 mpg avg., to a 12.5 avg. in just one day driving the same strip of interstate to work. Anyone out there had simular occurances with theirs. There has been no changes recently besides an EGR valve replacement. Thanks

 

Welcome to DF. I will move this to the appropriate section so you can get answers to your problem.

 

Probably just the computer acting up. There's no way you're average could drop from 17 to 12.5 in a single day unless you just idled all day or redlined it all day, which you didn't. If anything it might mean it's time for a tune up depending on the miles and when you last did a tune up.

 

The computer is only accurate after several fill ups so it can average. I can reset mine and get an average of 18mpg if I soft pedal. But after a few days, even weeks, it reflects the average of 12.2, which is much more realistic.