Electrical problem on targa 911t 2.4 1972

[pud]

Hello, can anbody help me here, im having running problems at the moment , plenty of popping at the stacks and also sometimes a backfire ,i took out a spark plug and it was sooty black , when i turned the ignition key so the dash lights were on and the engine wasnt turning over i looked at the plug i pulled and it was sparking all the time i never seen this before as i thought the pugs were meant to spark as the engine was turned over what is happening here any thoughts , pud