[Sandy G]

To answer your question about the drains: The 986 has four drain holes, two near the battery and two under the convertible top clamshell. Rainwater gets in these areas, and these drain holes let the water flow out to the ground. If the holes are clogged, water can end up leaking into the cabin.

Unfortunately, the (expensive) immobilizer is mounted on the floor of the cabin under the driver's seat. If the cabin gets enough water on the floor, the immobilizer can be damaged and cause a number of weird problems. Search Google for lots of videos, "How to clean 986 drain holes."

Most of the folks here are pretty sure your issue is the ignition switch, not the immobilizer. But it's a really good idea to keep your drains clear in any case, before you damage your immobilizer.