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I have a 1991 twin turbo awd,aws dodge stealth that will not fire on the #3/6 coil. I have replaced the following, coil,power transistor,crank angle sensor,plugs,plug wires, m air flow sensor,ecu. I am at my witts end. Sometimes when you first start the engine, the coil will fire for about 15 seconds and then quit again. Neither #3 nor #6 will fire after that Any help will be greatly appreciated