Dodge Ram 1500 running rough

if the guy thinks it is the O2 sensor then it probably is..... if you sensor malfunctions spurattically it will create a real rough idle by running a rich mix to the cylinders making it run like crap......when the engine light comes on it sends a malfunction code and if the guy was able to pull it and says O2 then it just needs replacing.....i would start with that the fuel filter is usually located underneath mounted to the frame or under the hood against the firewall on the drivers side...

I have had this same problem. You need to find out what the error codes are and the pending codes are. Also HOW MANY MILES ARE ON IT... This is a very important question. Also your service history. This sounds like fouled plugs caused by need of a valve job. Sounds like a big job, and it is, but with the right info, tools and time you can have this Truck running like new. I would first try Seafoam in the gas. Seafoam is a cleaner you can pick up at auto parts store. Works much better than STP fuel cleaner. The way you can tell is simply removing the spark plugs and inspect. If your O2 sensor is bad your check engine light should come on and stay on. O2 sensors don't go bad and then start working correctly normally. Check a few things and write back.