What is going on???

[flouese]

Top down enjoying the weather. Approaching a stop sign, engage the clutch, dash board lights up, car shuts down. Fired right back up, no other problems forthe rest of the drive. This has happened several times in the past. I assumed that it might be a fuel issue since it sat for several weeks. Fresh tank of 93 octane (as usual), but it still happened.

In summary, only happens when I am preparing to stop, either clutch in or coasting.
Car shuts down, but fires right back up.
Can/will someone point me in the right direction to remedy this annoyance? Im afraid it might happen while I am on the highway.

Please advise
99 base, 188K miles, engine replaced 15K miles ago with one with 84K miles.

[Stl-986]

you could still have bad gas in the tank. Put some Heat it in for a couple of tanks to help get any water out.

Could also be a loose ground wire. But as a test I would put it in neutral when coming to a stop and keeping the rpm around 1k to see if it happens.

[Quadcammer]

idle air control motor clogged or inoperative?

I'd remove, clean, test wiring connections and reinstall.

[Jeffd]

I'm new to Porsche but not new to cars and shade tree mechanic duty at all. My '00 Boxster S that I purchased a couple of months ago behaved in a similar way for the first couple of weeks of ownership. The first time was 4-5 days after I bought it when the engine just cut off in a sweeping left-hand curve when I went for an upshift, all dash lights came on. A couple of days later I drove around for a while, stopped at a store and it wouldn't start 15 minutes later when I came back out. It would crank and crank with a little tiny bit of tach movement (supposedly excluding the crankshaft position sensor as the culprit) but not start. It was near the house so I had my daughter pull it home. As soon as we got it home it fired right up.

A few days later the engine stalled in a left turn when leaving an intersection and shifting to 2nd but then started right back up. Finally, I guess I got "lucky" (because I was near all of my tools) and it failed to start at my house and wouldn't start regardless of how long it sat. I put a fuel pressure gauge on the fuel rail and had 0 PSI fuel pressure. I jumpered the fuel pump relay and still 0 psi fuel pressure. I replaced the fuel pump, it fired right up and I haven't had an issue for weeks. Based on the patina on the fuel pump and the fact that it looked like an OE part I assume it was the original fuel pump.

Anyway, if you can get a fuel gauge on there when it's misbehaving that's probably the proper troubleshooting method. If you can't but you suspect the fuel pump is the original 24 year old unit, it's got to be near the end of life anyway. I hate "throwing parts" at a problem but given that it was about $150 and the easiest in tank fuel pump replacement I've ever dealt with I'd probably just replace it if you suspect it.

Oh, I suspect that if I had put the fuel pressure gauge on there earlier I probably would have seen below spec fuel pressure. If you'd prefer to do intelligent troubleshooting you could check that.