I have read manual, looked online,and even talked to mechanic. I put new plugs, wires, ignition coil, fuel filter on the van. I can notice change when replacing new parts. It still doing it, spitting and sputtering like its going to die any second. I have noticed an exhaust leak in the system but its very faint. My other thought is the catalytic convertor giving false readings because of the air flow and amount of oxygen flowing through. Any ideas?