Hello,
In my recently purchased 2001 3.0 ffv ford ranger, I have a misfire in cylinders 2,4,6. Do you have any ideas?

 

I would compare the plug gap from one of the missing cylinders with the gap on the good cylinders. If the gap on the missing cylinders is high you may have the wrong plugs installed. 2,4,& 6 sounds like one whole bank with the problem. Your ignition is a waste spark system where half the plugs are fed current in the normal direction and half have a reversed current direction. You need to use double platinum plugs so both electrodes are protected. The original plugs had 3 of one type and 3 of another type, with each having different electrode protection. If one plug was pulled to get a plug number to buy replacement plugs, half the plugs would be unprotected and would wear rather fast. Just a wild guess but easy to check.

 

All of the plugs are brand new, just replaced. Had the misfire prior. Also tried replacing coil pack. No luck. Appreciate the effort though

 

misfires can be caused by burnt valves. the best way to to rule out burnt valves is do a compression test. pretty common with these motors. cold motor, all plugs removed.