My 03 Expedition 5.4 With 189K started misfiring a few months ago, it was running rough, the Service Engine light would flash and a ton of codes came on at once including 301 and 307 so I figured plugs and coils. I replaced all plugs and coils with Motorcraft brand and it ran great for a couple of months. Last month it did it again, same codes, same cylinders misfire, so after asking a tech a the Ford dealer I replaced the ECU. So now with the new ECU I only get 3 codes 300, 301 and 307... but it is still misfiring and not running at full power. I replaced the coil and injector pigtails for cylinder 1 because the plastic tabs were broken, but still no change. What next, should I change fuel injectors?