heater core problem on 2003 Mitsubishi Diamante

if the pipe or faulty
o-ring leaks from my heater core...what would it affect to make the neutral light flash alternately while im driving? and the car has poor acceleration...the car drives but i cant hear the transmission shift through each gear like it should. plse help

Asked by for the 2003 Mitsubishi Diamante
probably not related unless the heater core is leaking fluid onto neutral saftey swith or related wiring and causing interference,sounds like a job for a qualifyed shop