pressure regulator go bad? the diaphram went in mine. the one on the e30 only fills up the air box with fuel and will not start, yes a bad one of those in history too. the one on the 533 fills up the plunem and then the cylinders. man what a ROCKET SHIP!! seriously the exhaust got so hot it was glowing behind the cat at the axle cross over and the muffler blew out the welds and the internals were red hot. my wife was driving at the time with our two kids. boy am i lucky that it didnt ignite the gas tank. she pulled over to the side when the car started to miss and she smelled the smoke. melted the hell out of all the christmas chocolate in the trunk. THIS IS A DANGEROUS DESIGN ON THE M30 THE E20 HAS TO FLOW UPHILL TO GET TO THE CYLINDERS.