I have a 2011 Ford E350 Van (15 seater) with a 5.4 Liter Engine that has around 210,000 miles on it. While driving the van down a country road a few weeks ago, all of the sudden it started running extremely rough. I limped the van home and pulled the codes: P0300 (multiple cylinder misfires), P0302 (Cylinder #2 Misfire) and P0305 (Cylinder #5 misfires). I found it odd that two separate cylinders on two separate banks of the V-8 engine that don't even fire next to each other in the firing order would start misfiring at the same time. I gapped and replaced all 8 spark plugs, all 8 injectors and all 8 ignitions coils. The engine continued to misfire after I made those changed. Then I also changed out the MAF (Mass Airflow Sensor) and one upper bank O2 Sensor that got too hot while I was running the van trying to trouble shoot the issue. I have checked both the battery voltage and alternator voltage and both are correct. The engine is not loosing any coolant (so likely not a head gasket). Still, the engine continues to misfire on cylinders #2 and #5 and I am out of ideas. I mechanic friend of mine said it might be time to change the engine out but I am not sure I am up to that big of a task. This engine does not have a distributor for ignition but separate ignition coils. Any ideas of root cause of the dual cylinder misfire?

Other Symptoms: rich/fume smoke coming out of the exhaust and very hot catalytic converters (as one might expect with unburn fuel from cylinders #2 and #5 entering and likely burning in the exhaust.

 

Something for you to check,
Verify power and ground are getting to the coils.
The coils should have power anytime the key is on. The PCM is what supplies the ground signal to each coil
This can be easily verified with a simple test light.
Depending on what you find there will determine where we go next.
We know fuel is getting to the cyls by the rich condition..
A compression check would be a good thing to do and would eliminate any mechanical problem if up to spec.

 

I had the same problem on my 2006 with the 5.4. Threw parts at it...finally gave up and took to dealer. Wiring harness breaks causing the issues. $800 repair (all labor). No issues since. OBD codes only indicate a status problem. Sometimes the source is not what the code indicates.