I purchased a 2000 Ford Ranger last year. Within the first two months of ownership, the vehicle was having a cylinder 4 misfire. To fix it, I replaced the fuel filter, plugs, wires and cap - replacing the wires, plugs and cap fixed the issue. The issue went away for four months when cylinder 4 misfired again. I brought it to a repair shop and they again replaced the wires and plugs. The vehicle now has a cylinder 6 misfire.
There has to be something causing these plugs to continually go bad. Rather than just replacing the plugs again, I’d like to attempt to be proactive and fix the root of the issue. I’ve googled the issue and some of the forums seem to indicate a bad EGR valve. Can someone please help me?!?!