[Porschepetter]

Hey guys, I need some help with my 1976 911S 2.7L.

The car shuts off after it gets warm—usually around 30 minutes of driving. This started around the same time I noticed the charging light came on. The tach has also started jumping around.

Here’s what I’ve done so far:
• Suspected bad grounding, so I replaced the ground strap from the transmission to the chassis.
• Swapped in a new ignition coil.
But the issue is still there.

I’m starting to think the alternator might be shot, and that I need to replace it to keep a stable current to the car. The injection system does rely on steady voltage to run properly, right?

Could it be the CDI box? The car starts easily and runs fine for 30 minutes, so I’d assume the CDI is OK—or am I wrong here?

Any ideas on what I should check next?