starts at time other imes will not

[cajunwolf]

at first thought it was the fuel filter change it truck work fine for a couple of days then started where it was really hard to start had fire and all but would not run engine turns over fine . change cap and rotor then change coil since the engine started one ime and ran but al of a sudden just stop like someone would have turn the switch off crank the engine over and will no run so change the icm on the fire wall and still does the same thing have power to the coil when turning the engine over but it doesn't show it coming from the spark plugs has me thinking it might be the pcm but none of the books i have give me any idea where it is any help would be very helpful