Ranger 3.0 Misfire

[davargo]

A few weeks ago my CEL came on, showing a misfire on cylinder 3. The truck still drives alright, but there is noticeable shaking at idle and at about 1700 rpm. My mileage has also dropped off pretty suddenly.

I switched plug wires, got new plugs, made sure spark was getting to the plugs, and tested the resistance of each injector. All checked out fine, and I still had a misfire. I did a compression test today and measured the following pressures:

1: 140 psi
2: 140 psi
3: 95 psi
4: 120 psi
5: 145 psi
6: 100 psi

Cylinder three is the worst, but 4 and 6 are also noticeable lower than the others. As far as I can tell this is a valve/ring problem, but is it worth the cost of a teardown to fix this on three cylinders? I have 123k miles on it, and can't afford to buy something else right now. How much would it typically cost to have a shop take this apart and fix whatever may be causing the misfire?

I would just let it go, but the mileage is getting worse all the time and cold weather is setting in...

 

[dankhimself]

how did the plugs look on the low cylinders?

 

[Original_Ranger84]

You would be much better off finding a used motor in good shape and swapping that in, it would probably be easier and cheaper then getting a shop to rebuild your current motor.

 

[davargo]

Three of the plugs looked pretty scorched, like they had been running really hot for a little while, but they did not correspond to the cylinders that have low compression. If I remember right, the plugs from 1, 4, and 5 looked the worst, while the others looked fine. I also noticed that 3 had raw fuel on the plug when I pulled that after idling the truck for a few minutes, but the others were dry.