Lost
 

I have a 2000 E 150 5.4 ltr 175,00 mi with the following problem: engine ran hot, a bad heater hose, for a minute or so. Corrected heater hose and refilled with coollant. Afterwards it ran fine until next day when the engine began running rough and "loping" at idle and bogging down knocking under slight excelleration. No OCBII codes. Checked for vacum leaks, cleaned and inspected MAF, cleaned and tested EGR valve, tube and ports. Replaced DPSE sensor and IAC. Same problem. Seems to run fine at higher speeds. Did I kill the engine or am I missing something?

Usually when someone describes the engine as running rough it usually is misfiring.
I know you said no codes, but with the engine idling feel the exhaust coming out the exhaust pipe. If you feel a put,put sound or puff it is misfiring. Sometimes when an engine is run hot it can burn a valve which can produce a misfire. If you cannot find and confirm there are no vacuum leaks you may need to have a compression test done. This would tell you if there is a possible valve problem. To speculate at this time isn't wise until some tests are done. Are you sure all the coolant that leaked is gone and not some of it is sitting in one of the holes the coils and spark plugs share?