I have changed coil packs and spark plugs. 3.7 6 value engine it cleared the code. I drove the truck bout 300 miles the next morning started truck engine light came on Run test again and code 303 misfire on number three cylinder I have no smoke out exhaust not using oil could it be a sensor gone bad
Could be poor compression, faulty sparkplug/ wire and injector on no.3
October, 3, 2013 AT 4:51 PM
Several things could be an issue. Since you already replaced the coil packs and plugs, I would recommend that you check engine compression on that cylinder to make sure it is within the manufacturer's specs. For only one cylinder to misfire, it is either an electrical issue, fuel injector issue or weak compression.
Tell me this. Can you feel the cylinder misfire? Does the truck shake?
October, 3, 2013 AT 4:59 PM
I was thinking about your truck and had some after thoughts. Check these things too
---Check for Carbon Tracks on the Spark Plugs and inside the Spark Plug Boots. These conditions will cause the Spark to bypass the Spark Plug and jump to ground on the engine.
--- make sure that the Misfiring Cylinder is getting Spark.