So I've been needing a vehicle thats better on gas in a bad way. I asked around and got in touch with a guy selling an 00 ranger 4x4 5 speed. He said it had a miss and all it needed was plugs and wires. ( I can remember telling myself that out of the dozens of trades I've been involved with over the years I have heard this exact "conclusion " more than a few times. Its never actually been the case. Furthermore if its such a great truck and thats all ot needs why didn't they just do that themselves since they changed out the motor themselves. ) despite all the visible red flags I got the truck. I PAID for it too. Apon further investigation the plugs and wires were new already so guy just lied to my face. (Hard to believe nowadays) ANYWAYS....I've read up on it all I could find but im stuck. I know the 2 engines have completely different firing orders. I've had it over a month and haven't got to drive it at all besides limping home. So it does run. Just very rough. Like won't hardly pull out of its tracks

 

If it just has misfires then very WORST CASE is swapping heads with rebuilt, or getting those heads a valve job at local machine shop

All engines with valves get burnt exhaust valves which cause the midfires, 3.0l Vulcan seems to get them more that others but common issue on all engines

Best case is someone wired up spark plug wires in the coil wrong, common goof

If the coil pack is on the drivers side of intake and side ways then it should be wired like this
1 2 3
5 6 4
front

If its on the passenger side long ways then
3 4
2 6
1 5
front

The 5 6 4 side is OFTEN miswired, because is not 1 2 3, lol

Ford V6 cylinder numbers are
3 6
2 5
1 4
front

So follow EACH spark plug wire to its cylinder

Next will be a compression test, all spark plugs removed for the test
If some cylinders are lower than the others that causes the misfire, and that means you need to fix the valves

A replacement engine(used) is often just "buying someone else's problem" and you have already done that, and it don't feel good

But if thats what you want
1986 thru 2008 3.0l Vulcan engines can be swapped between years, that's not an issue
And Rangers and Mazda B-series only used the Vulcan model 3.0l OHV, avoid 2004-2006 3.0l Vulcans, bad exhaust valves, lol
Ford has other 3.0ls but they are much different than the Vulcan, but same firing order, lol, its a V6 balancing thing, even for Chevy V6s, same firing order