I am going crazy with my "03 Taurus. It has 153,000 miles and it came down with a misfire on cylinder 1. So, I changed the plugs and wires. Still the mis. Then I changed the coil pack, still the mis-fire. Mass air flow changed, IAC changed, TPS changed. Then I can't find a vacuume leak. I have run, DP fuel system cleaner, along with Seafoam through the engine to clean up the internals of the motor. After that it runs smoother but, the car still runs rough and sometimes stalls at stop lights, bucks when driving down the road. I know that the miss will make it run rough but I don't know of any where to look.. Has anybody had this happen to them? The local dealer is not the best at troubleshooting these problems. They told me that the computer sometimes "Drops Drivers" in the computer and defaults to a clyinder 1 mis-fire.? Has anybody heard of this. I just don't want to buy a new car because of this.

 

A clogged injector &/or spark plug wire routing could cause it also.

 

Try switching the # 1 plug wire with a different cylinder and see if the misfire moves with it.
Agree with the possible malfunctioning injector suggestion by joepenn.