I have a 2003 S-type 3.0L that is throwing a P0191 code (fuel rail pressure sensor range performance). The car will run fine for a few miles and then start to chug. Turning the car off will temporarily solve this but I need more that that. Fuel pump was changed 12 months ago with an OEM Jaguar pump, new fuel filter put on a week ago, and cleaned out mass air flow sensor. Planning on cleaning out throttle body tonight. Any other suggestions as to why my Jaguar is "chugging"?