Could be.... 10% ethanol doesn't help in any grade. Plus, stations don't monitor the amount of sediment that collects in the bottom of their tanks that can gunk up filters and injectors.

I have a 2003 3.0 and for good measure I perform the "seafoam" injector cleaning about every 6,000 miles because of the potantial for build up. You can get it at O'reilly's or Autozone. I change the fuel filter about every 10K.