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2000 taurus with duratec motor. I was out running errands a little bit ago and i was sitting in traffic and all of a sudden my engine started idling a little rough and the check engine light came on. At first is was just blinking and then it stayed on all the time. Acceleration is slower that it was and there is a slight hesitation when the pedal is pressed. Temp hasnt changed and the fluids all look alright. It kinda sounds like one of the plugs isnt firing when i listen to it. It is still warranty from the lot that i bought it from. It covers powertrain and all that, just wanted to know what to look for. Any suggestions.

Thanks,
Shannon