I've got a 2003 Ranger 2.3L DOHC, 5 speed, 2WD. It has a check engine light with codes-
P0316-Engine Misfire Detected On Startup
P0704-Clutch Switch Input Circuit Fault
P2195-O2 Sensor Excess Lean Signal Bank 1-Sensor 1
P0171-System Too Lean (Bank 1)


The truck runs fine when coasting or accelerating but when holding a steady light throttle to maintain speed the truck starts bucking and jerking. It's doesn't feel like a misfire, more like a fuel cut out condition. When this happens and you come to a stop, you can smell that the exhaust is very rich coming out of the tailpipe. I've already replaced the upstream O2 sensor and I did a tune up about 15k ago. I'm thinking fuel pump or fuel pressure regulator. Any ideas?


I doubt if this is related, but on start up (more so on a cold start up) the A/C compressor clutch kicks in and out 3-5 times and makes a terrible racket.

 

Engine misfire can cause a 'lean' condition, even with excessive fuel being supplied(flooding, even). The O2 sensor responds to excess(not burned up) oxygen in the exhaust, giving a 'low' voltage signal. Get it hot, and in an exhaust gas stream with no O2's and it will develop a voltage. Feed it unburned fuel & air mix, and it will notice the O2's that are not burned, and report "Sir, there are extra O's, so you must not be sending enough fuel..." Rong. And the computer may well add more fuel just to make up.
So, check your plugs & wires, coil(s), etc and determine if there is a spark problem.
Most times, codes should be handled in the order received. Fix the ignition or misfire problem. Check fuel pressure and delivered volume. Most gauges will allow you to divert the fuel into a container to check volume over time. If pressure or volume (filter?) are low, the injectors may be sending to little fuel, and it is lean.
Bad plug wires can cause bucking and jerking, what I call 'trailer hitching' acting as if there was a towed trailer that was jumping around, jerking the truck.
tom

 

For these 2.3L Duratec engines the Forscan software from forscan.org is a real life saver. I would highly recommend looking into it especially if you are going to keep the truck for a long time. The software is free but you'll need to purchase a cable or OBD2-bluetooth adapter depending on how you use it. Once using it the only thing you won't be able to monitor is fuel pressure and oil pressure because there are no PID's in the ECU for those.

Also, tomw had mentioned above "So, check your plugs & wires, coil(s), etc and determine if there is a spark problem."; and so to add to that, the coils on these engines seem to crack over time causing the same symptoms you described. Although my coil wasn't causing any problems I did find a hairline crack in it and so I replaced it just for good measure.