Engine stumbled a couple of times after a few minutes of driving, then it was fine for a while, and it stumbled again and ran fine. My first thought was water in the gas. On my way home today the engine cut out and I had to coast to the side of the road. I cranked it over and on the second try it started and it ran fine all the way home. The problem is intermittant. Electrical, ignition, or fuel? (I have a Petronics module in the distributor). Where do I start? Thanks. It is a 75 914 1.8L with Ljet injection.

Which year car do you have? Need to know the engine type and if it has a carburetor or is it fuel injected?

75 914 1.8L with Ljet injection

It may be hard chasing down an intermittent problem, but you should start with the basics. Check the valve adjustment, if you haven't so already. Also, check all rubber hoses for vacuum leaks. It may be worth while to check your distributor cap, rotor, plug wires and plugs to be on the safe side. Post a few pics of your engine bay. What is your idle speed? After starting, does the rpm (idle) drop after a few minutes of run time? I suspect vacuum leaks, grab a can of ether and start blasting away.

check all wires leading to your coil, inspect coil wire. I had a similar problem on my first spring ride, sputtering, bucking....then stalled and wouldn't
start, luckily only a block from home. it turned out to be a disconnected coil wire. if it was only one spark plug wire your engine would run, although very roughly.