It may be a simple fix, it may not. However, when you gas up, make sure you ALWAYS turn the cap so it clicks at least 3-4 times or more (I always do it several times). If you don't, you will get the message you're getting about the gas. This is a simple fix. Try it next time you fill up and see what happens. If that'* not it, you need to go get it checked...probably a bug in the computer.
I had to get my computer recalibrated because it was choking out my car at about 20,000 miles. The tech just told me the computers sometimes "fall out of calibration" and they need to be taken back and re-calibrated.
Hope this helps!