[RickMN]

You usually don't get vapor lock on a fuel injected engine. The fuel pump keeps the pressure pretty high in the fuel rail and that's what eliminates vapor lock. This actually sounds more like either a clogged fuel injector or an injector with an intermittant short. A clogged injector would leak gas into the cylinder after a shutdown or leak too much at idle, causing rough running. Try dumping a bottle of Chevron Techron fuel injector cleaning fluid into your tanks. It's the best add-in cleaner on the market. The problem could also be a bad fuel pressure regulator--which also might explain the frequent fuel pump failures. If the Techron doesn't solve the problem, it's time to find a good technican and have them run a fuel injector resistance and current draw test on each injector. Also run a scope pattern on the fuel pump and a pressure check on the regulator.