I've had my 280z for about 7 months now and it was running strong until one day I was changing the spark plugs and I stripped the port so long story short I just brairly fixed the thread on the spark plug port and got the spark plug in and hooked up the battery and the gauge only read 12 volts so I hooked up the jumper cables to see if it will move but nothing and now the car just doesn't want to start any help btw 1976 280z stock l28