I have a unusual problem with my 1986.5 Porsche 928 5 speed manual. car is super clean and has had no problems. Recently the car takes more engine turnovers to start over a day or two. then by third day it turns over but does not start at all. My mechanic is baffled. He says when it sits with the battery disconnect turned off and he goes to turn the battery back on the car starts fine.
when the battery is left turned on after a day or two and he goes to start it wont start. It turns over fine but will not start. any suggestions?