04 grand am runs fine but after it warms up it starts to miss realy bad changed plugs and os2 some ome tol?

04 grand am runs fine but after it warms up it starts to miss realy bad changed plugs and os2 some ome told me it could be ignition module ? i have no idea any help appeceated but like i said car only starts missing after i drive it for little while and it misses bad when it starts turning on air will kill it .