I have kept track of my fill ups, which is how I got my averages of 280 miles city and 300 miles highwway. I'm positive that all ignition components are fine, as Lorainfurniture stated, there is no hesitation or misfire. I checked my spark plugs weeks before the issue occurred just because I did a valve stem job and wanted to make sure they were not being coated by oil (this caused me to fail smog)....dry as a bone. What I did do is purchase some seafoam and poured it into the gas tank the other day to see if it would help. Hopefully it was just dirty injectors or something. Thank you all for your input. If seafoam doesn't clean out injectors or if the problem was something else, I will do a search on testing duty as I'm not familiar what that is or how its done.

I tried sea foam and I think that stuff is not good. Try buying a bottle of redline fuel additive. It can be found on amazon. I tried everything first, and the redline was the only stuff that made a dramatic difference on the first tank.

that happened to me in my SD.I set the parking brake one to many times she stuck,and my mileage went down.I spend money before I knew this,then smelled the brakes and knew it was this.Fixed the brakes and mileage came back,then a year later back again.This time it was a stuck caliper,one I replaced by two months.That happens with calipers I see now.You might feel your rear wheels or fronts after a drive.

Thanks for the heads up!