More engine woes.

[orange72350]

So im driving to school this morning, and all of a sudden my trcuk stalls in the middle of an intersection. I start chranking on her, and theres nothing. I get a tow, and take the truck to the shop i work at. My boss and i start in on it. Low and behold, theres absolutley no spark. So, i replace the hei module and the rotor. The truck starts and runs now, but for some reason it will stall if i mash the throttle through the floor. If the engine doesnt stall off the line, it stutter all throughout the rpm range. If i hold the throttle to the floor, it will stay steady and run right, but the moment i hold the throttle steady at 1 rpm point, it sputters and coughs. What gives? ivve been told its the coil, but i really dont know where 2 go. Could somebody please save me here? im fricking lost man!!!!