Definitely sounds like GP issues. Mine will stumble a bit with one bad GP, but it's a real PITA to start with two bad GPs. It will try to start while the starter is spinning but die as soon as you release the starter. When it does start it feels like there's a bunch of unburned fuel that takes quite a few seconds to clear out. I would do a good test on the GPs before getting into anything else. If in doubt, pull them out and bench test them (carefully).