I have a 1985 gt, it has a 351 Windsor in it, with MSD ignition. Now my problem is when I put the car in gear it dies if I'm not giving it the gas, and if I turn on my heater or my lights it will die if it's not moving. I just bought a new battery for it so I don't think it's the battery but I'm open to any suggestions, this is my daily driver so I need as much help as I can get