I have a bad misfiring between 45 and 50. I have re[placed all plugs, wires, and flushed the fuel injectors. Any help would be great.

 

Just had a similar problem with my f150 ... Its probably a pcv problem. At least that is what the problem was with mine. This is what you should do. If your real savvy with a wrench and feel you can make repairs by yourself go buy the chiltons manual for your make and model. Read the book and locate the pcv valve and replace it, but heres the final part.. check all the small tubes on and around the back of the top of the motor. Look for cracked, loose, broked hoses.. It should be a small L shaped hose connecting the pcv to the intake manifold. Its probably got a hole in it or is worn out.. Replace the broken hoses with the proper type of hose. Finally if you dont find your solution there.. Ask around for the most up to date technical repair shop and have them do a level 3 compression and mixture test.. Your probably running lean on the gas/air mixture side because of a broken pressure control tube or something like that pcv does not stand for pressure control valve.. but I forget what it stands for. The lean mix is causing the computer to **** up at high speeds. Maybe this is your problem maybe it is not .. but try it out It cant hurt to look right..?