1998 4.6 bad backfire!
I recently got a 1998 F150 4x4 with the 4.6 v8 in it. It has 212000 miles on it, and came up with a code for misfire on cylinder #3. The sparkplugs looked kinda old so I figured that they may be the problem. I put in new autolite plugs and wires and gapped them to .054. Now I have bad backfire under acceleration and it runs rough. I Have checked everything, the connections are in the right order. They all seem to be firing fine too. I checked the injectors with a screwdriver and they all seem fine. I have poured multible engine cleaners down the throttle body and they haven't fixed the problem either It ran fine before I did all this, so I'm very confused on what it could be. Does anyone have any idea what this problem could be?