The motor in my car has just been replaced - I don't even have the thing back yet - but now two injectors are "bad". The dealership says it was running super rich and rough after the swap, and diagnosed it to bad injectors on rotor 1. It was running perfect before, except for the blown water seal.

Is this common, or at least reasonable?

They are currently waiting for the aftermarket warranty to inspect and decide if they are going to cover the replacement. Most likely they will not. So it's going to come down to replacing it through Mazda.

Suggestions?

 

get your car away from the dealer as soon as possible, and take it to someone who knows what they are doing. It is posible injecctpors are bad or plugged, but since they were working before, I doubt it. Probably just dealer not knowing what to do. take it somewhere else, that dealer will screw up your car.