Having a problem with mt 2003 GT. Every now and then (not all the time) she sputters around 1600-1800 RPM while cruising, or under normal acceleration till it gets past it. Can't seem to figure it out. I've changed the fuel filter and air filter. Last year, I had a blown plug which I repaired with the CalVan insert kit, and at that point I replaced all plugs (properly gapped) and coil packs. I have also gotten fuel at least twice from different stations. I'm not throwing a code.