I have a 94 4.0 4x4 that acts crazy. Some times it runs great some times it bucks and surges and u cant push the gas pedal more than half way down or it just dies. It has an intermittent cel and the only code is for the o2 sensor. New coil pack, wires ,plugs,fuel filter . Any help would be great.

 

How many miles? What code? (which O2 sensor?)
Give the MAF a cleaning.

A weak (magnet was very faint) old crankshaft positioning sensor once made a family member's car run real bad.

I believe any Throttle Positioning Sensor can go bad with age.