My 2000 ford ranger 3.0 v6 is running kind of poorly. I'm 99% sure that cylinder number 6 is missing. I replaced all the spark plugs and spark plug wires and it is still missing. I then unhooked the #6 spark plug wire from the co pack and it ran the same. But when I unplugged another wire it started running even more poorly. So I was wondering if anyone had any ideas as to what the problem is. I'm guessing the coil pack maybe??? Please help.

 

When you pull the plug wire on 6 can you see/hear the spark jumping from the wire to the plug...if yes do compression check on that cylinder...if not coil pack or wire..they updated it new part #...comp check if thats good above 140psi suspect injector....lower comp below 80psi could be valve problem..

 

Welcome to the forum

Pulling spark plug wire on Coil Pack systems doesn't always tell you much.
The V6 coil pack only has 3 coils inside, cylinders #2 and #6 SHARE a coil.
As do 3 and 4, and 1 and 5
Hence the coil packs spark plug wiring
[3 4]
[2 6]
[1 5]
Front

This is called a Waste Spark system, used in single cylinder magneto 4-stroke engines since early 1900's

Anyway because 2 spark plugs are firing at the same time you can Reverse the #2 and #6 spark plug wires on the coil pack if # 6 now works and #2 doesn't then yes it is a coil pack issue.

When you changed spark plugs #6 should have been a different color than the other 5 if it was misfiring.
Was it?

If so then check it again, clean it and the swap #2 and #6 wires on coil pack.
Run engine and see if #2 now shows the misfire color.


Engine gasoline runs on 3 things
1. Spark, at the right time
2. Fuel, mixed with correct amount of air
3. Compression, above 120psi

I use an old spark plug to check spark, hook up the spark plug wire and ground the plug, I use a Jumper cable to hold plug, other end connected to battery ground.
You need a blue-white spark, yellow means weak spark.

To check fuel, I disable the coil, unplug its connector
Crank engine a few times, then pull out the spark plugs
They should be wet with fuel, if one is dry then fuel injector issue.

Compression is actually the first thing I check because it can't be intermittent, you either have compression or you don't.
You can chase you tail around with spark and fuel when you had a compression issue all along, lol.
So if you test it first then it is off the table and you can know spark or fuel is the issue.