If the car sits for several days, it starts fine. If the engine is off for just a few minutes, it also starts fine. It has problems starting, however, if the engine is off for a couple hours.

This problem happened before. The dealer said that the plugs were fouled due to a rich fuel mixture, which was set to resolve a rough idle. After cleaning the plugs, the engine started easily in every situation. This time, however, they claimed to have checked the plugs and nothing was wrong, but the starting problem remains. The service manager is speculating that it could be a problem with fuel pressure and I should take it in. I am skeptical.

Any thoughts?