I had a CEL and misfire two weeks ago and codes said cyl 1 misfire and two more cyl pending. Cleared codes and problem went away. A week later I had another CEL:
P0302: Cylinder 2 Misfire Detected
P0303: Cylinder 3 Misfire Detected
Pending Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected
P0301: Cylinder 1 Misfire Detected


Again, cleared and went away.
Ran fine for a week and yesterday got two CELs:
------------------
P0300: Random/Multiple Cylinder Misfire Detected
P0303: Cylinder 3 Misfire Detected

Pending Fault Log
------------------
P0304: Cylinder 4 Misfire Detected


And:


------------------
ECU reports no current faults

Pending Fault Log
------------------
P0304: Cylinder 4 Misfire Detected


Any ideas?
TIA,
Vince

 

right cat most likely. depending on mileage, coil connectors are a maintenance item so id be doing those anyways.

regardless, i would bank on the cat.

 

Took the car to dinner (three miles RT) and all was good until we got to the driveway and I felt it stumble. Pulled/reset codes and restarted. Smoked like mad! Tons of unburnt fuel.

 

Go back to basics. Do a compression test; check coils; check plugs and wires; make sure connections are all solid. Do a search and you will find how to do all of this.

 

+1

 

Indeed I am all about the basics for troubleshooting.

 

Hydro locked at start this morning. I hope it didn't bend a rod...

 

Sounds like a bad fuel injector. Hydrolock is not good. Regular use of a good fuel system cleaner (I prefer Techron concentrate every 2K) will prevent carbon buildup and injector failure.

This is what a 3/4 tank of typical 10% gasoline did to an E55 after sitting in storage for a couple of years in Florida

 

Seen this issue before

Had this issue before also (mine would sound like it had a lumpy cam) - multiple missfires on the bank it is failing on and would run pig rich

Had a couple of mates have it too

Failing Primary O2 Sensor - in your case bank 1

One free way to confirm is that you can monitor it in the Torque or DashCommand App and when the error occurs you will quite possibly see the O2 sensor volts lock onto a voltage and stay there OR go out of range 1.0V and up or 0.0V

Another free test would be to swap both primary o2 sensors over and see if the errors transfer to the bank 2 cylinders

If no change that is when I would swap coils and plugs around to see if the issue follows

 

It hydro locked with fuel. Has to be injector(s) dumping raw. I had it towed to a local indy yesterday. I will report back!
Vince

 

Hopefully, it's just a bad injector.

 

Failed #4 injector. Have to pull intake manifold. Prolly replace all eight while inside.

 

Glad to hear it was nothing real serious. Good idea in replacing all 8 while you are at it.

 

Don't let them hose you. There isn't really an intake manifold. It's all part of the supercharger. Only the surge tank covers need removed to replace the injectors. I'd also have a compression test done just to make sure a rod isn't bent.

 

Thanks for that. I will keep an eye on them. I don't want to know..

 

1200.00 all in including eight new injectors, two spark plugs, oil and filter. Car runs perfect.

 

Could've installed larger injectors yourself along with all new plugs for about half that.

 

I know.. I would rather do what I do for a living and pay for some stuff that way. That being said, I do enjoy building engines for my race car and would have a tough time letting someone else do that for me!