2005 E450 Ford V10 intermittent misfires

[Valpo_Camper]

My 2005 class C is built on a 2004 frame with the Ford V10 in it. It has developed an intermittent misfire this year but not enough to give a CEL.

Google searches tells me that it probably needs new plugs to cure this.

I am planning to replace the plugs despite their low mileage although being original. Rig only has 26,000 miles on it. Should I do coils at the same time or just the plugs?

[opnspaces]

Sometimes you just gotta bite the bullet. But at least it's fixed. Now on to life's other adventures.

[Valpo_Camper]

Well I can do quite a bit under the hood of a car but this job kicked my butt and humbled me to applying the credit card wrench to it. 3 different cylinders were misfiring plus random misfire code is what the shop came up with. Replaced all 10 plugs and coils and did a fuel system cleaning. Runs like a big heavy smooth box again.

[Krusty]

katleman wrote:

bobndot wrote:
CEL can light-up due to a bad or dirty electrical connection from the ECU to the sensor.

My mechanic always checked that at my service intervals.

And specifically throw only cylinder misfire codes (P0300 & P030X), no other codes?

We’re talking once a mile or so.

Check and make sure the center bolt holding your harmonic balancer on has not come loose

[katleman]

bobndot wrote:
CEL can light-up due to a bad or dirty electrical connection from the ECU to the sensor.

My mechanic always checked that at my service intervals.

And specifically throw only cylinder misfire codes (P0300 & P030X), no other codes?

We’re talking once a mile or so.

[bobndot]

CEL can light-up due to a bad or dirty electrical connection from the ECU to the sensor.

My mechanic always checked that at my service intervals.

[Grit_dog]

^Very frustrating when competent diagnosis fails. Good news is it runs just fine I suppose.
Your rig is new enough that chaffed wires, corrosion etc are lower on the list of possible causes, but if there’s any areas on the injector, coils and or main ECM harness you haven’t checked, including unplugging all harnesses and just looking for visual damage to the pins or connections, that’s where I’d likely go next.
And it’s not out of line that you may have picked up a furry traveler along the way who likes multicolored licorice (wire insulation) or spent a night or 2 in pack rat country and they snacked on some wires.
If you have camped where it looks like everyone is working on their engines (hoods up), they’re not. You’re in packrat country. And those things are pure evil to vehicles and other things.

[katleman]

zigzagrv wrote:
Did you check your battery voltage? Had a similar situation once where after I would stop for a short while and when restarted, it would run rough and throw codes till I got up to speed. Turned out battery was bad and till the alternator built up voltage, this would happen. New battery solved the problem.

Battery is new this season, replaced proactively, not out of need.

The codes are thrown at idle, up hills, down hills, doesn’t appear to vary with load.

[zigzagrv]

Did you check your battery voltage? Had a similar situation once where after I would stop for a short while and when restarted, it would run rough and throw codes till I got up to speed. Turned out battery was bad and till the alternator built up voltage, this would happen. New battery solved the problem.

[katleman]

Been up in Alaska all summer, my 2016 E450 Ford V10 (26,000 miles) has had the CEL on for the past five weeks. According to my OBD2 scanner, it first started throwing P0300 (generic misfire), then it claimed cylinder 2 was the culprit (P0302)

Replaced the air filter as it was filthy. Nope.

At the point its flagging 4 different cylinders, split between the two sides, had a mechanic diagnose it, suggested bad fuel or water. Tossed in SeaFoam and iso Heat. Nope

Refusing to believe it’s the plugs/coils on 4 cylinders, as they are good for 100k miles, tried replacing the MAF sensor. Nope.

Bit the bullet and replaced all the plugs and coils. Nope.

All through this period of misfires, which was flashing the CEL once a mile, no loss of power, no loss of fuel economy, drove just as it always has.

So I’m heading homeward with the CEL flashing, run out of things to check or replace. Stumped every mechanic I have consulted.

[way2roll]

Valpo Camper wrote:
Well the saga continues on this and my scanner.

Went and scanned the RV and my scanner will not give me misfire data on the Ford engine. WTH??? Updated software on the scanner and will go back and test again. If all else fails I will try the cowl off in the dark to check. I do not hear a tick but we shall see what gives.

Not sure when your plugs coils and wires were replaced last but it may very well solve your problem even without diagnosing a particular cylinder. AS one coil fails it stresses the rest and in turn they can also misfire. Just replace the coils and plugs and go from there. They probably need replacing anyway. Willing to bet it solves your issue.

[Valpo_Camper]

Well the saga continues on this and my scanner.

Went and scanned the RV and my scanner will not give me misfire data on the Ford engine. WTH??? Updated software on the scanner and will go back and test again. If all else fails I will try the cowl off in the dark to check. I do not hear a tick but we shall see what gives.

[Cruisineasy]

Might sound a bit weird but, If you hear a ticking sound when the misfire happens I would pull the doghouse off and run the engine when its dark. Then you might see a spark caused by an electrical "leak". Just something easy and costs nothing.

[Grit_dog]

Grit dog wrote:
^Yes some reports were loose spark plugs, but how you know if it was actually loose if it’s not connected to the engine anymore. Some would loosen, but I doubt anymore said hey that’s loose, let’s leave it and see if it blows out…
The root cause of the early 2V engines (not yours) was only 4 threads in the heads. They were revised to 8 threads and that helped quite a bit, but didn’t totally eliminate the problem.

So not a V10, but later model 5.4s in cutaway chassis apparently spit plugs too.
Was talking to my buddy this afternoon he was driving home in his 2015 E350 work van. 100k miles. Spit out its second spark plug. Last one was a few years ago.
Idk if the “newer” cutaways still have the old 2V heads or what.
PS he’s a die hard Chevy guy but inherited 3 Ford vans with the company he bought.

[Valpo_Camper]

Alright, figured out today how to get misfire data out of my scanner while I was scanning my Audi so now I can go to storage and scan the C.

Good news to me is the Audi has no misfires for quite some time but it is due for plugs soon. No need for coils in it at the moment even despite its advanced miles, 230k miles