Help...missfire

Just found the site today. Looking for suggestions regarding my 03 G. I replaced the cap, rotor, plugs, pcv valve, intake gasket, valve cover gaskets and tube seals. The car runs worse now than it did before the tune up. Mileage has gone to shit, idles at 500, have to 2 foot it at stop signs. I replaced some questionable vacuum lines, traced the misfire to cylinder 5, replaced that plug again and reset the ecm. I see that I should be using premium fuel, will be filling it up tomorrow. One weird thing when I did the tune up. I swear the rotor was pointing in a slightly different position between the old one and the new one. I don't know if it was just me being tired or if the part was cast wrong possibly. I did use Bosch platinum plugs, and will change them, AGAIN, to NGK R's. PLEASE HELP

Bosch plugs blow.

You may need to clean the throttle body and MAF sensor.

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Is there still a cylinder 5 misfire? Also, is the car running rich? If the ignition system is fine, it would be worth inspecting the fuel injector.