My 2003 H6 outback is cranking but not starting. I had this same problem with my 2004 legacy until one day the whole car shook and the engine stopped working and died. The mechanics could not diagnose the old issue - checked battery, belts, head gasket, and starter, but no luck.

What might the issue be? It has always been a little hard to start - need to hold the key on for a couple of seconds, but now it won't start at all.

 

Fuel pump? 14 years is a good age for one.