Very low MPG

I was in a very minor accident in a parking lot where we were both backing out, and the other SUV (Trail Blazer) backed into my driver's side rear wheel. Right away I noticed the alignment was way off and my MPG was calculating at about 8.5, normally I average about 20 to 21, and the electronic stability/traction control light was on. Had a bent toe link (wheel support), so I fixed that and the alignment, and stability control light is gone. Seems okay otherwise, but the system is still only calculating 8 to 9 MPG, and I appear to have gone through almost half a tank in three days. That is about one hundred miles at most, nearly all of which are highway miles. I reset the MPG calculator then too, but it is still terrible. Two Jeep dealers never heard of this happening, and I am not trying to pay $100.00 plus for them to check it out since it is not covered under warranty. Seen a few similar issues one to two people had online, but no solutions. Any help at all, ideas of what I personally could try, or thoughts of what it could be would be much appreciated! Thank you in advance!