Ecoboost Performance Forum

Ecoboost Performance => Troubleshooting, Maintenance, TSB Articles => Troubleshooting => Topic started by: blownbyyou on April 19, 2017, 12:19:15 PM

Title: P0304 Misfire in Cylinder 4
Post by: blownbyyou on April 19, 2017, 12:19:15 PM
So last night I was driving home and unfortunately my 2011 SHO decided to crap the bed. I was wondering if anyone has had this issue before...

On the expressway i gave it a little gas (not past half throttle) and saw check engine light start blinking, then notice a definite miss fire. I pulled over and ran the code and got the above code.

I had it towed to an independent shop and they think its an injector and I am thinking I agree because i noticed last night that the afr on one bank was 14.xx and the other bank was 9.xx.

They don't really seem to want to do the job, was wondering if anyone has done it or if its another issue?


P.s. the car has a unleashed tune on it with a 3 bar map (running fine before that).
Title: Re: P0304 Misfire in Cylinder 4
Post by: ZSHO on April 19, 2017, 12:32:34 PM
IMO it sounds about right!!!. Any smell of gas asociated with the above symptoms?
FYI It's Bank 1 front passenger side injector.
Check # 4 spark plug for fouling.
Do you have any type of warranty?  Z
How many miles on your SHO?
https://www.autocodes.com/p0304_ford.html (https://www.autocodes.com/p0304_ford.html)
Title: Re: P0304 Misfire in Cylinder 4
Post by: blownbyyou on April 19, 2017, 12:36:45 PM
0 smell of gas that i noticed...

No warranty...

67k on it the car..
Title: Re: P0304 Misfire in Cylinder 4
Post by: SHOdded on April 19, 2017, 02:18:45 PM
Deebeaux had written up and videoed his experience R&Ring fuel injectors.  Tedious rather tham difficult with some mechanical ability.

http://www.ecoboostperformanceforum.com/index.php/topic,6430 (http://www.ecoboostperformanceforum.com/index.php/topic,6430)
Title: Re: P0304 Misfire in Cylinder 4
Post by: blownbyyou on April 19, 2017, 03:59:18 PM
Sooooo i went to pick up the car from the mechanic shop as they said they didn't want to touch it.... as i was driving to another location the car fixed itself and is now running fine.

WTH..
Title: Re: P0304 Misfire in Cylinder 4
Post by: SHOdded on April 19, 2017, 04:15:53 PM
Do not worry, if you miss the misfire, it will come back :P  seriously though, new gas, new gas station, ...?
Title: P0304 Misfire in Cylinder 4
Post by: MiWiAu on April 19, 2017, 04:17:14 PM
If it IS an injector (sounds like the same symptoms when I had an injector crap out) then you should be covered to 7 years/70,000mi under the "long term defects" warranty.

https://www.ford.com/resources/ford/general/pdf/2011Warranty.pdf

Smell of fuel will be stronger from the tail pipe. Check your oil and see if it shows over-full or has signs of a fuel smell. You could also pull cylinder 4 plug and see if it's wet. Mine was soaked with gas. If that looks fine, you could swap cyl 4 coil with another and see if the misfire follows the coil pack.

Driving with a stuck injector can overheat and melt the catalyst.

Did they give you any additional evidence that pointed them to an injector vs something else?

Keep us posted!


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Title: Re: P0304 Misfire in Cylinder 4
Post by: blownbyyou on April 19, 2017, 05:32:05 PM
Quote from: SHOdded on April 19, 2017, 04:15:53 PM
Do not worry, if you miss the misfire, it will come back :P  seriously though, new gas, new gas station, ...?

No....its weird as heck..
Title: Re: P0304 Misfire in Cylinder 4
Post by: blownbyyou on April 19, 2017, 05:38:31 PM
Quote from: MiWiAu on April 19, 2017, 04:17:14 PM
If it IS an injector (sounds like the same symptoms when I had an injector crap out) then you should be covered to 7 years/70,000mi under the "long term defects" warranty.

https://www.ford.com/resources/ford/general/pdf/2011Warranty.pdf (https://www.ford.com/resources/ford/general/pdf/2011Warranty.pdf)

Smell of fuel will be stronger from the tail pipe. Check your oil and see if it shows over-full or has signs of a fuel smell. You could also pull cylinder 4 plug and see if it's wet. Mine was soaked with gas. If that looks fine, you could swap cyl 4 coil with another and see if the misfire follows the coil pack.

Driving with a stuck injector can overheat and melt the catalyst.

Did they give you any additional evidence that pointed them to an injector vs something else?

Keep us posted!


Sent from my iPhone using Tapatalk

Thanks for the link, i am at 67k so i need to watch that for sure...

So i just checked the oil and it does have a slight smell to it, but it is at the full line (not any higher)..

When I was driving it i would try to keep it above 2.5k and it would run fine...
Title: P0304 Misfire in Cylinder 4
Post by: MiWiAu on April 19, 2017, 05:48:41 PM
Immediately after shutting down, mine was emitting white fuel vapors from the exhaust. Mine was stuck wide open (I suspect). The tech reported that the oil level was over-full on the dipstick, and I had quite a bit of gas in my OCC for that drain cycle.

(https://uploads.tapatalk-cdn.com/20170419/41f1cedd542bccfb5e1ccc0eb08c5fcf.jpg)

I didn't want to take any chances and had mine towed to the dealer. This was about 3,000 miles after I bought it (got it used with 29k mi). :(

(https://uploads.tapatalk-cdn.com/20170419/756bd757a41e23cc6b5dd861f2e78ff4.jpg)

P.S. I finally replaced my turd excuse of a mailbox, so I'm no longer the shame of the cul-de-sac (at least not because of my mailbox).


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Title: Re: P0304 Misfire in Cylinder 4
Post by: ZSHO on April 19, 2017, 06:16:14 PM
I would try swapping the Coil Pack to a different cylinder and monitor for any codes.
R Plugs original at 67K.?
The other option is to have it Diagnosed with IDS Software to perform an injector Flow Test.
Due add your signature with your current vehicle and any mods you may have,thanks and best of luck to ya. Z
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