[DaveCap]

I was getting the CEL with a few cylinders showing misfire plus the random misfire at start up. I did the BG injector cleaner and all seemed well. Started to get the codes again. Never did it feel rough or odd. Driving home the other night, I accelerated up a hill on the highway and I got the restricted performance message along with the flashing CEL. This time it showed misfires at all cylinders plus the random and a low fuel code. I got it home and I put in a few new coils I had. No change. I took it to my indy. He reset the codes, new readout said misfire only in #5. He changed the injector. Didn't cure it. He says it seems to be from only one bank now. I forget which. He's now checking vacuum. I've done countless searches and have yet to find a definitive answer. Anyone have any thoughts that could help me along here? I don't want to keep chasing my tail here.

5.0 N/A 129,000 miles

 

[Mrmerlin]

and even more important,
what is the code reader identifying as cylinder 5.

NOTE there seems to be 2 or three different cylinder layouts for this 5.0 engine ,
and what the mechanic sees from the shop manual versus what the code reader will see from the engine computer .

I have not ever fixed any of my rough idle running issues since the timing chains have been swapped,
and it seems a compression test might be the next thing to do just not motivated to take it apart again.

 

[RRSC2012]

Do you solve the issue?

 

[RABarrett]

There are several possibilities for misfire , which will set codes. They typically involve the ignition, such as worn plugs, or compromised wires arcing to ground. They can, however, involve fuel related issues, including lean mixtures or oiling of the plugs. As the fuel pump dies,its ability to deliver fuel is compromised. A dying fuel filter will do the same thing. You might look at fuel trims, bioth short term and long term to check for the computer's compensating, or attempting to do so. Ray

 

[RRSC2012]

Second bank Long Fuel trim is negative ~14%, Short Fuel Trim looks ok

 

[RABarrett]

Does the -14% show up on both banks? Ray

 

[RRSC2012]

Does the -14% show up on both banks? Ray

only on bank2