Working from the apparent 'rich' condition on start-up from prolonged sitting (more than an hour), it sounds like gasoline is leaking into the intake manifold. (A single fuel injector would foul only that cylinder had you would have a miss, but the engine would start normally otherwise.) The leak into the manifold can be either : 1) the cold start injector is leaking, or 2) The fuel distributor diaphgram is cracked and leaking.

You can easily test (1) by removing the cold start injector, plugging the hole in the manifold with something, disconnecting the electrical wire to the injector, and starting the engine. A leaking injector will drip/leak fuel quite obviously. Even a drop every 20 sec will flood out a sitting engine.