computer replacement for '04 PT 2.4 HO w/turbo, AT

I have been chasing cause of a low idle misfire for couple years now. When under acceleration & @ cruising speeds the eng runs fine w/plenty of power. Mileage currently around 90k. Have done all checks for compression, leak down, cleaned upper intake manifold ea time removed, replaced plugs 2x w/correct plugs per decal under hood, plug wires, coil, crank sensor, cam sensor, had computer checked @ dler, who said was an injector problem, so replaced all 4 injectors, coolant sensor, timing belt(along with several items nearby), and nothing has improved anything, except last go around with removing & cleaning injectors seems to have made car idle faster(still missing when at low idle ), so now we have to hold brake down harder to keep it stopped. That may be a leak around seals but haven't located it yet if it is. Thought I would go ahead & replace computer( # 292AD) anyway so got an LKQ w/91 day warranty, Installed it but car would only start, run a second or 2 & die. I called LKQ supplier & was told I may have to have LKQ computer programmed by dlr to my veh to make it work. Is this true? I figured it should be simple plug in & go or the computer supplied is defective. I also noticed some reports to check the coolant fan 2 spd relay. I will do that also. Another possibility is wiring harness short but haven't found anything obvious yet. Anyone else have any more suggestions/solutions? But, first I need to resolve computer issues before warranty period runs out. Thanks.