Drove the car for about 30 minutes and parked for 15-20 minutes to get some food. Hopped back in and it won't start. The starter engages but no joy. Did it about 4-6 times. Had to push start the car

By the way, when I first start the car cold. It hunts excessively to almost where it dies then it settles a bit after it warms up. Still hunts but not as much. Not sure
if it is related to the issue I described above.

Appreciate any feedback. Thanks.

The problem is the head temp sensor thinking the engine is cooler than it really is and causing a rich mixture. Next time before you turn the key on, push the throttle down to the floor, then start. My 76 does this also and otherwise runs great.
Tom

what is "no joy"? a new mechanical term? if I knew that it meant "it won't turn over" or "it turns over but won't fire" I might be able to help. Clear questions sometimes get clear answers.

"It turns over but won't fire" and yes, "no joy" is the 914 term for "it turns over but won't fire". By the way, I am not new to this forum, joined in 2005 but thanks for the welcome anyway.

Thanks Tom. I'll try that try trick. Appreciate it.

I agree the head temp sensor is the problem and the resolution, having just addressed the problem. They are inexpensive and although the servicing requires adapting either the socket or the extension that fits into the socket to allow the lead to exit without cutting it, it was a small effort that paid off in the confidence of knowing it was done right and won't plague me further.

Thanks. Looks like it will be the next weekend project.

The head temp sensor is working!
The problem most of the time is this: The heads are aluminum, barrels are cast iron of some type. Aluminum cools off much faster than than the core of the engine. Head temp senses a cooler condition than really is needed, sending that signal to the ECU to enrich the mixture. When in fact a richer mixture is not needed. Simple solution is to start the car with the throttle wide open, opening the throttle before turning the key to on. If you turn the key on first, depressing the throttle fully will send a signal to the ECU to give the injectors a few milliseconds extra pulse, resulting in making the problem even worse. This was learned from a thread I started several years ago because my 76 was doing the exact same thing. Paul Anders answered the thread with this explanation. It works for mine every since. Even the owners manual has a part that says when starting, fully depress the throttle.
Paul and I discussed putting a parallel resistor in the circuit controlled by a switch on the dash to turn to on when ever it was hot out to initially start the car. We both figured it was too much to do for the small number of times it would be needed. A resistor in parallel with the temp sensor would lower the temp sensor resistance, causing a leaner mixture.
hope this will work for you also. No need to replace a good temp sensor only to continue to have the problem still be there. Unless of course, you are having other running issues, then the temp sensor may be going bad and need replacing.
Tom

Thanks for the explanation. Makes a lot of sense. The car runs pretty good except the "hunting" issues I described in my initial post. Does the CHT sensor have anything to do with the "hunting"?

I spent several hours chasing the same problem on a customers car. Wouldn't idle after warm, had to hold pedal to floor, ran poorly with no guts. Cht had the proper ohms both cold and hot. Mps checked good, adjusted TPS. After much frustration, I unplugged the harness to the ecu and connected it to another of the same part #. The sucker fired up, idled steady, and ran much better than it ever had before. It now starts first crank every time no matter the temp. First ECU I've ever seen go bad. If everything is in spec, there will be no need to depress accelerator ever! Hot or cold!

Really,
makes me wonder why Porsche decided to put the following in the owner's manual.
"Before starting, depress the accelerator pedal fully and keep at full throttle until the engine runs. This applies when the engine is warm or cold and during all weather conditions."
Tom

35 yr's later, it might be a moot point. These cars have aged to a point that they all have unique personalities. I have a 76 that starts and runs fine whether I depress the pedal or not. On the other hand, my 73 likes the pedal depressed. Go figure.

I think not everything Porsche said and designed is gospel. My parts guy swears that everything the engineers did was for a reason, and it must be that way. That must be why we have a hook for a clothes hanger where no shirt could hang.

If your ignition switch has never been replaced-consider replacing it. I just had mine replaced due to a similar situation this weekend and now it starts on the first try. Easy to do, and there is a good procedure on Pelican Parts.