[Bigtoe32067]

I need some expertise and help on an issue I'm having with my beloved Porsche

I have a 99 996 that I've owned for about 18 years. It sat for about 6 months and now it turns over but won't start. It has no fuel pump prime when first turning the key on either.
Here's what I've done
Jumped the fuel pump relay and the pump comes on but still won't start.
Replaced the fuel pump relay still no prime and nada
Replaced DME relay still nada
I scoped the crank sensor and got AC voltage but couldn't find specs for what it should be so I replaced it and you guessed it, nada
Car has just over 100k miles on it and had always been very dependable

Anything I'm missing? I'm open to suggestions or thoughts.

I'm thinking ECU and if it is then my next questions is can a Durametric Pro program a used ECU from another car to this car or do I need to tow it to the dealer?

Thanks
Tony