I HAVE A FIAT MAREA 2.4TD  WAS RECENTY USING USED COOKING OIL IT BLOCKED ALL INJECTORS AND AFTER CLEANING THEM AND THE TANK, FEUL LINES AIR LOCK KEEP COMING BACK AFTER 20 OR MILES. IT WAS OK ON MOTORWAY DOING 80MPH  BUT ON LOCAL KEEPS CUTTING OFF, BUT IF I LEAVE ENGINE OFF TO 10 MINUTES OR SO IT STARTS AGIAN DRIVES FOR A FEW MILES TO GET HOME.  DOES ANYONE KNOW WHY IT HAPPENING?  BEEN TOLD IT MAY B THE SEALS IN THE DIESEL PUMP.