A month ago my Ac system was replaced, due to the fact my Condenser Coil was leaking power steering fluid. a week ago, while coming to a stop, the truck began to idle lower than normal. few minutes later when stopped, truck idled low again but this time the truck cab and steering wheel shook very aggressively. This happened on and off the next few days until i realized it only happened with the ac on. Also during this whole time i never noticed any difference in performance or sound of the truck, with or without ac. Only issue, Truck idles rough with ac on while stopped / in park. i just hit 121k miles. Had my spark plugs and coil packs replaced at 90k. The shop i took it to called back today and told me they replaced all the spark plugs and coil packs. Meanwhile he couldnt explain why it only happened with the Ac on. Told me 3 of my coil packs were not allowing the spark plug to operate correctly. All the Vans i use for work have the 5.4, ive seen my fair share of blown packs and plugs and plug misfires with them over the years. My truck has had no symptoms like ive seen with the work vans. Now im now mechanic but ive been Doing HVAC my whole life, so this just doesnt add up to me. Slightly confused. If anyone has some higher knowledge or opinions, id appreciate it. thanks.