Engine Misfire Code 309 Itasca Sunstar 35F (V10)

[geneb1737]

I have a Itasca Sunstar 35f with the Triton 6.8 V10 engine and it is throwing a code 309. This is a misfile on the number 9 cylinder but my engine runs smooth and no apparent misfire that I can detect. This code usually shows up when the engine has at idle for a couple minutes but has never appeared when at power. The local ford dealer replace the serpentine belt thinking this might be the problem but the code has appeared again. Since then the code has appeared again. Any help is greatly appreciated, thanks.

 

[creativepart]

I’m kind surprised that the dealer would replace a serpentine belt for a well known V10 misfire issue… but OK.

The Triton V10 has a long history with spark plugs failures, spark plugs wire failures and coil issues that lead to misfires… and even spark plugs being ejected out of the head.

Seems like that is where any Ford dealer worth their salt would start on a V10 misfire.

 

[Morich]

Just as a random guess, did the shop actually hook up the machines that tell them about the engine and how it is running? Since misfires can be caused by a number of different things from plugs to wires to timing, just throwing a guess at it sounds like a simple way to just charge and move on!
Sounds like a good time to find a different shop! My family has an auto dealership background and one of the problems has become much like the health/doctor issue.
As groups have become larger and larger, with less interest in the individual problem at the time, there is often a drive to simply get more business by getting this one out of the way!
Have you had a doctor visit where they spend more time checking and correcting the past visit info than they do asking about the current issue? I see very much the same in automotive repair!

Like your doctor, they may have to actually do some looking at details of what the engine is doing and that requires more than just listening to how it runs!

 

[geneb1737]

I’m kind surprised that the dealer would replace a serpentine belt for a well known V10 misfire issue… but OK.

The Triton V10 has a long history with spark plugs failures, spark plugs wire failures and coil issues that lead to misfires… and even spark plugs being ejected out of the head.

Seems like that is where any Ford dealer worth their salt would start on a V10 misfire.

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[geneb1737]

I am not totally convinced that it is a misfire issue since I have not witnessed such while driving the vehicle or at idle while the check engine light comes on. Just looking to see if anyone else had the same issue and could give me a clue.

 

[creativepart]

Lots of others online with this and similar issues. Here's a thread on IRV2.com which might get you some help.

07 V10 chasing Misfires - iRV2 Forums

Long time reader, first time poster. I have a new to me 2008 Winnebago SightSeer 35j on a 2007 F53 V10 with 44,000 miles. Fuel Filter was replace unknown years ago at 33,973 miles Took a 300 mile trip

www.irv2.com

Just do a Google search for "Ford V10 code 309 Misfire issues." This engine is used on thousands of RVs and many non-Winnebagos so really, it's not a "winnebago" problem it's a Ford F53 V10 issue regardless of manufacturer. So, rather than hope for someone here with this issue to respond, expanding your search will get you the most responses from other owners.

 

[AlanO-WO]

My brother in law had one of these. Drove from Florida to NY and along the way blew out one of the spark plugs after repeatedly getting misfire codes.
I installed a Helicoil in the stripped out head with a new set of plugs and anti seize compound. The aluminum head is very easily damaged. Really bad design.
Makes me glad I drive a Mercedes Sprinter!