Miss fire on #1 and #3

I have a 2001 ford windstar the codes are bank 1 lean ( wires have been cut) could this cause the miss fire on the #1 and 3 cylinders? The previous owner put copper plugs in it instead of platinum. How hard is it to change the plugs?j

No the cut 02 sensor should not cause miss fire. I would suspect coil pack do you have good spark at the plugs.

I have not checked for spark trying to do the cheapest first

Copper plugs will simply wear out faster (30-50K or so), but won't cause problems being copper. If the plugs aren't Autolite with the single ground electrode, THAT could be a problem. However, almost always it's that coil pack as the previous poster indicated. Take it off, flip it over, and look on the bottom for tiny cracks. It's a common failure.

I have not checked for spark trying to do the cheapest first

It's not expensive to pull a wire and see if there is spark there.

Turns out to be the coil pack.thanks

Turns out to be the coil pack.thanks

It usually is on these vans. Thanks for following up and letting us know!