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Update on Scored Cylinders

Inthehighdesert

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You’re not wrong. I was referring more to just ignoring it.

If the coil swap solves the problem.

If it doesn't then he may have to try to reproduce it. I don't like it either, but without knowing whether it's spark or fuel related and it not showing up until high RPM, there aren't always a lot of ways to find the source of the problem.

Hopefully the coil solves the issue.
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Cobra Jet

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Thought:s

You should also post this in your original thread, because many who were helping there in that thread can add their opinions there with your additional findings. Also it helps because people just seeing this thread do not know the entire history/story behind this post.

IF the coil was bad (ANY of them), you would have had a distinct “P0305” DTC which would have been for cylinder #5 coil pack. If all you were getting was a P0300, which is a very generic “misfire” that’s not enough to determine or say for fact that it was coil #x.

S550 distinct cylinder misfire codes are like this with the # denoting the actual cylinder:
P0301
P0302
P0303
P0304
P0305
P0306
P0307
P0308

Had coil # 5 been bad, and swapped to cylinder #2 location, the car should have then thrown a distinct “P0302”.

I can’t tell from your posting IF that is what the shop did do by getting distinct codes or just “guessed” by moving parts around and assuming that was the issue. I would hope the shop did get actual DTC’s before doing any work instead of throwing parts at it…

Did the shop give you the old coil back? If new, It should not be throwing distinct misfire codes after a new coil IF the shop did in fact replace the bad coil with new.

Check the harness plugs going to the coils and make sure none are broke and none are loose. A loose plug will throw a distinct misfire too.


A random generic code like the P0300 is a PIA and no one on here would be able to give you a definitive "it's this part".

This thread may give you some enlightenment to Ford's misfire strategies:
https://www.mustang6g.com/forums/threads/good-tech-article-on-ford’s-misfire-strategy.108076/
 
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11GT50

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IF the coil was bad (ANY of them), you would have had a distinct “P0305” DTC which would have been for cylinder #5 coil pack. If all you were getting was a P0300, which is a very generic “misfire” that’s not enough to determine or say for fact that it was coil #x.

S550 distinct cylinder misfire codes are like this with the # denoting the actual cylinder:
P0301
P0302
P0303
P0304
P0305
P0306
P0307
P0308

Had coil # 5 been bad, and swapped to cylinder #2 location, the car should have then thrown a distinct “P0302”.
This is where I'm at without knowing more. And at this point is why I'm speculating that it could be fuel pressure related.

What information did the tech have to determine a possible spark related misfire and swap the coils? Or was it a stab in the dark?
 

UpACurb

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*last comment. It seemed like the conversation ended with us agreeing to disagree. I basically said I will not, not drive the car hard -- should I change the coils?

He said I shouldn't change the spark plugs and drive the car normally.
How far are you from Upland CA? reason Im asking is the owner of Upland Ford is pretty active on the Facebook GT350 forums and the crew over there knows GT350s pretty dang well....the owner had a GT350 he does a little racing with .....still has the VooDoo - I think he drives his hard all the time with no issues lol They actually do all their work on 350s at their fleet center if you want to PM me I can provide you with the contact info for who I dealt with .....

1772420932472-gm.webp


1772420991567-26.webp
 

GrabberBargeCaptain

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battery and a coilpack seem to be the low hanging fruit here. is its the original battery, they don't last for 10 years anymore especially not with the underhood temps of these cars nor the hot CA summers.
 

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honeybadger

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How far are you from Upland CA? reason Im asking is the owner of Upland Ford is pretty active on the Facebook GT350 forums and the crew over there knows GT350s pretty dang well....the owner had a GT350 he does a little racing with .....still has the VooDoo - I think he drives his hard all the time with no issues lol They actually do all their work on 350s at their fleet center if you want to PM me I can provide you with the contact info for who I dealt with .....

1772420932472-gm.webp


1772420991567-26.webp
While I agree getting it to Christian and team would be a huge upgrade over these guys, I promise you he’ll tell you to CPC swap it 😂
 

sk47

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They mentioned contaminated fuel but said their initial concern was a base engine issue and that the engine would need to be torn down.

*noting that I added in iso heet to my fuel and put in new Chevron gas and the car was fine driving moderately hard.
Hello; I had been following your initial thread. Just found this one. I read this new thread and am up to date.
I selected the somewhat dismissed fuel based on the photo in the previous thread. My concern being contaminated fuel sems to have been overlooked. It may not wind up being important but could be helpful to know what, if anything has been done about the fuel.

1) how many miles are estimated to have been run since buying the car or a guess as to how much new gas has been added? (Point being has enough new fuel been added to dilute the old fuel.) (Dismiss this question, maybe, if you have run several tanks of fuel down to 1/4 and filled up)

2) I do not know if Ford puts a fuel filter in the Mustang. If so, might be worth a filter change. Something I do on a regular basis anyway if a vehicle has a filter.

story #1 -A friend had an old 1972 Porsche 911. He would let it sit in an unheated garage for months, sometimes more than a year, with less than a half tank of gas. He only called me when it would not start. I would get it started, suggest he not let it sit and the cycle repeated. The metal gas tank rusted on the bottom inside from condensation of water. Pulled the tank and did a clean and then a coating of the inside with POR 15.
The car was mechanically fuel injected so had a low-pressure fuel pump and in the engine bay a high-pressure pump. I plumbed in a clear fuel filter between the gas tank and the low-pressure pump. That way I could check for rust. The fix held for many years but the let it sit cycle continued. I moved away so no longer work on his cars. Last I heard his new mechanic found rust in the add on filter.
Story #2 - I had a Ranger bas boat in the 1980's. One summer the boat wound up sitting around during the hot months. I went fishing On Cherokee Lake one night. Boat had two six gallon tanks. I emptied one tank and switched to the other. The engine started sputtering and running bad.
Got it home and took the carb apart. Jellied fuel was clogging it. I let the fuel sit too long in one tank. I started using Stai-bill after than in anything not run regularly. Now there are fuel stabilizers formulated for E-10.

Again good luck.
 

WItoTX

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I think you should do some more pulls. Just to really make sure the light turns on. Like could you get the light to change from bright orange to angry red?

Just kidding. All advice has been offered. Here just to stir the pot.
 

sk47

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Hello; I looked up Iso Heet. It is isopropyl alcohol which has been used for decades to remove water in fuel. I used to use the stuff every winter along with keeping the tank topped up.
Most modern fuels have ethanol alcohol blended in. Most common is E-10 which is a 10% blend of ethanol + gasoline. There is a push to up it to E-15. You can get E-85 as well.

The iso-heet additive was a problem saver back when tanks were metal and fuel systems were open to the air more. Tanks condensed water in the tank. The water is denser than gasoline so over time the gasoline and water separated to wind up with a layer of water with the gas floating on top. You could wind up with an inch or more of water in the bottom of the tank. In cold weather the water could get into fuel lines and freeze.

The isopropyl alcohol mixes well with water so would be added to help with the freezing in fuel lines. Here is where I may show some ignorance. I am fairly confident that ethanol alcohol also absorbs/mixes with water. I stopped using Iso-heet back when E-10 and tighter fuel systems came along and have not had problems. My thinking being the ethanol would do the job of the Iso-heet. My thinking may be off.

Anyway I think it is known an E-10 pump mix has a problem, maybe two. If alcohol blended fuel sits a while the alcohol and gasoline will start to separate. I have read at six months such can start. That is one problem.

I am less confident of the next idea. If the ethanol also absorbs/mixes with water the thought is two things might happen. One is the alcohol will mix with enough water to affect the way the fuel burns to some degree in the engine.

Second is the alcohol likely has a maximum capacity to absorb water. Once the maximum amount is mixed then extra water will become a layer on the bottom of the gas tank. That would explain the three distinct layers in the picture of your fuel.
 

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Tycoon

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Thought:s

You should also post this in your original thread, because many who were helping there in that thread can add their opinions there with your additional findings. Also it helps because people just seeing this thread do not know the entire history/story behind this post.

IF the coil was bad (ANY of them), you would have had a distinct “P0305” DTC which would have been for cylinder #5 coil pack. If all you were getting was a P0300, which is a very generic “misfire” that’s not enough to determine or say for fact that it was coil #x.

S550 distinct cylinder misfire codes are like this with the # denoting the actual cylinder:
P0301
P0302
P0303
P0304
P0305
P0306
P0307
P0308

Had coil # 5 been bad, and swapped to cylinder #2 location, the car should have then thrown a distinct “P0302”.

I can’t tell from your posting IF that is what the shop did do by getting distinct codes or just “guessed” by moving parts around and assuming that was the issue. I would hope the shop did get actual DTC’s before doing any work instead of throwing parts at it…

Did the shop give you the old coil back? If new, It should not be throwing distinct misfire codes after a new coil IF the shop did in fact replace the bad coil with new.

Check the harness plugs going to the coils and make sure none are broke and none are loose. A loose plug will throw a distinct misfire too.


A random generic code like the P0300 is a PIA and no one on here would be able to give you a definitive "it's this part".

This thread may give you some enlightenment to Ford's misfire strategies:
https://www.mustang6g.com/forums/threads/good-tech-article-on-ford’s-misfire-strategy.108076/
Question: do do you know what occurrence causes P0300? How is it detected and by what 'sensor' is it detected (for lack of better language on my part)?
 

sk47

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A random generic code like the P0300 is a PIA and no one on here would be able to give you a definitive "it's this part".
Hello; Here is my WAG on the code and codes in general. If we are very lucky a code might show a very specific part to be at fault. My take is often the codes merely point at some recognized anomaly. I get an impression some think codes and computer systems will tell us exactly what to do. Not necessarily the case.
I am going to try to make up an example but may miss the mark so those who know feel free to correct. Say a code shows up for a sensor. We would like to think it is the sensor at fault.
May not be the case. Might be the sensor is out of a predetermined range and something else is causing such. Replacing the sensor will not fix the issue. Seems to me a generic" code may at best point you in a direction.

A code for a random misfire may be not much better than you feeling the misfire from the seat of your pants. The trio of basic needs to run an engine are fuel, air & spark. Sadly, in modern cars computer-controlled spark & fuel are complicated.

The first fuel injected car i owned was a 1972 Porsche 914 with the BOSCH K-JETTRONIC fuel injection. Fairly simple compared to today's stuff. May have to check air, fuel and spark systems. Start with the easiest first. Look at the air filter for example. Not likely a clogged air filter is the issue but at high engine loads might be a factor worth a look.
 

VBGT350

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Wasn’t there a common wire breaking point near one of the pigtail connectors causing same codes?
 

melown

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How far are you from Upland CA? reason Im asking is the owner of Upland Ford is pretty active on the Facebook GT350 forums and the crew over there knows GT350s pretty dang well....the owner had a GT350 he does a little racing with .....still has the VooDoo - I think he drives his hard all the time with no issues lol They actually do all their work on 350s at their fleet center if you want to PM me I can provide you with the contact info for who I dealt with .....

1772420932472-gm.webp


1772420991567-26.webp
can upland ford change tires on carbon gt350r wheel without messing it up? I was looking for a good place to service a gt350, like a coolant change soon. I do the oil, trans, diff, and brake services.
 

UpACurb

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can upland ford change tires on carbon gt350r wheel without messing it up? I was looking for a good place to service a gt350, like a coolant change soon. I do the oil, trans, diff, and brake services.
Check out Wheel Warehouse in Orange CA.......they have an "exotic car bay" - they do a ton of high end stuff/ have done the wheels on tons of SEMA builds.......this is where I take my R .......I have had them do 3 tire changes now without issue (3rd time was due to a flat so had them do just the rears- but other times I had them do all 4)
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