could be a plug, could be a coil, could be an injector, if anything was really wrong I'm surprised it didn't throw a code.
If your mechanic is willing to do the plugs for that price, get it in writing, and make sure he knows if the plugs snap off in the head, as they are prone to do, he eats the time labor, parts, and tool to get them out. Make sure he understands the process and has a copy of the TSB
If it is a Ford warranty hand it to the dealer and make them fix it, their scanners are far superior to anything available to local shops.
Last edited by Neggy; 12-25-2009 at 08:51 PM.