I'm wondering about this cuz me and a friend have been dealing with a truck that starts to miss around 1800-2000 rpm and is hear related. If it's cold it won't hardly do it, after it runs and gets up to temp you can make the whole truck shake at that rpm. The cab just came down for the 3rd time with a 2nd set of heads because it seems there's a valve or 2 hanging open. Has new lifters, brand new ford injectors, cam and crank sensors replaced twice, FICM, swapped computer, swapped throttle pedal, injector wiring harness you name it. Seeing that "1800" rpm caught my attention because were stumped.