I have a misfire in #4 cylinder w/ SES lite flashing sporadically

A flashing check engine light is usually a result of ignition misfire. It indicates you may be sending unburnt fuel through your exhaust, which can quickly damage your catalytic converter. Have a diagnosis done as soon as possible. I suspect you may have secondary ignition issues (wires?).

coil assm on your truck are common and very easy to do dealer parts are the cheapest i find for these just buy 1 there plug and play