I have a 94 4.0 4WD manual ranger xlt. I have replaced the plugs, coil, and wires. It feels like a misfire. Should I check compression? I unplugged the iac and it levels out but still has a slight skip. It's sitts steady at 600 then hiccups to 500 then back up. This is warmed up and at idle in neutral.

 

Welcome to the forum

4.0l OHV has wide spark plug gaps, 0.054", were the spark plugs gapped that wide?
Narrower gaps cause rough idles

Run a can of Seafoam or similar injector cleaner in the gas tank, my 1994 4.0l gets a smooth idle, I do it once a year

Check coil pack firing order
3 4
2 6
1 5
front

The 5 6 4 side gets me every time, lol, follow the wire to the 4 5 or 6 cylinder as well

Yes, a compression test is always a good idea
Cold engine
All spark plugs removed
Test each cylinder, write it down
150-160psi is expected

 

Ok so I have replaced the iac and the issue went away for a week an dthen came back. I am considering doing a full induction cleaning. If this is a good idea please let me know.

 

Unhook one of the battery cables for 5minutes, or longer
Then reconnect
This clears computer memory of "learned" data
IAC Valve voltage is "learned" data
i.e. 10.5volt = 800rpm, 10.4volt = 775rpm, 10.3volt = 750rpm, ect................just made up voltages and rpms, point is computer "learns" what voltage = what RPM on any IAC Valve as all will be slightly different, and smaller vacuum leaks also change voltage/rpm settings
So you want to dump it all and get computer to "relearn" it

Sure clean the throttle body and intake, won't hurt anything