i have a 01' w/ a 4.0 sohc w/ 170,000 mls. A month or so ago it'd misfire here & there, eventually it started throwing the code misfire cylinder 4 & running lean on bank 2. i changed spark plugs & wires, no change. long story short ive replaced the coil pack, lower intake gasgets, cleaned the mass air flow sensor, changed spark plug & wire twice to cylinder 4, checked my erg valve, its fine, checked ground, changed both oxygen sensors. when i replaced my lower intake gaskets i noticed i had oil in my intake so i said ok pcv stuck open, changed it out, no change. im stumped any ideas would be helpful.

I had the same problem. It was a cyl 5, ended up being a bad wire. I also had the lean code beforehand. That was solved with a new intake gasket though.
If you have the lean code still, you have a vacuum leak. I took mine to a shop and paid 35 bucks to find the leak for me, then fixed it myself. Well worth it.
Not sure why you have oil in your intake but I have that problem as well. Thinking maybe blown or leaking head gaskets but not sure.
Did you torque your intake bolts to spec?

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Also have you read this sticky?

http://www.fordrangerforum.com/4-0-s...look-here.html

Vac leak could be in the PCV elbow.

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|'97 Ford Ranger XLT 4X4, 4.0L OHV| 5-spd, 4" suspension lift on Skyjacker M95's front/Nitros rear, 33" Trail Digger M/T's, WARN hubs, K&N, Fabtech Desert Guard, Custom Skeleton tailgate, 44 Magnum shifter, custom throttle cable mod, one-piece drive shaft swap, dumped exhaust, partially rebuilt top end, Amsoil 185k

Thanks the link you gave me really helped. It's looking like my problem is the vapor canister purge solenoid, like 240$. Gonna have to shop around. Thanks again.