[destabrook]

I have a 98 Ranger 4 liter with 133k miles. it started running very rough all of a sudden, so i scoped it and got a #4 cyl misfire code. I changed plugs & wires (needed) and o2 sensor . it is still running rough and getting the same error code. any suggestions?

[Dominick]

What code did you get?

[destabrook]

p0304 generic cyl4 misfire

[Dominick]

Here is a list that I found on that code.
OBD-II Trouble Code: P0304 Cylinder 4 Four Misfire Detected

[Boghog]

You might want to inspect the intake manifold upper and lower sections.The O-rings have a tendency to dry out and crack causing a vacuum leak which will cause a misfire.Try spraying around the intake with come carb cleaner especially around the suspected cyl.To replace the o-rings is about a one hr job and the parts are less than 30 dollars

[destabrook]

Thanks for your help.