I have a 1967 cougar xr7 with a 351 Cleveland. when attempting to start the car the starter comes in just fine but i can shut the key off and take it out while the starter continues to turn the motor over. ive replaced the ignition switch and the starter solenoid, neither of which rectified the problem. i believe it to be a hot wire that is faulty somewhere in the harness. any ideas where or any different opinions?