Got a problem with my 2wd Cosworth. It starts and runs sweet but after running for a few minutes it first starts to miss then cuts out and won't start. Remove plugs fit new it fires then the same happens! Every sensor is new, l8 ecu is ok done by msd and obviously works as car runs ok at first, timing is right, all sensors gapped correctly. Plugs when removed are black but not wet. Any ideas?