Relay problem?
 

Our Odyssey 2000 occasionally will sputter/die when starting - as if fuel pump is not engaging. Left it with Dealer all day but they did not have solution other than possible clogged fuel injector. Driving home, I hear a whirring motor noise from a/c when vent dial or recirc. dial is moved. I'm not very knowledgeable about cars but find it odd that I would have a different problem crop up so soon after coming from the dealer.

Are the AC relay & Fuel pump relays interchangeable? Could the mechanic have switched them when problem solving?