cylinder 1 missfire

my car is a 2001 mercury cougar with 45000 miles slow driven. The code readc 301 missfire cylinder 1 checked plugs and wires all good reset the code went to the dealer now they say the light hasnt come back theres nothing wrong. Car still missfires hesitates and surges causing bucking at low engine speeds between 1000 and 1500 especially going up hill with minimal gas pressure!!