Flashing check engine light multiple misfire codes

[larr12]

Same gas in the tank? If you already put more gas from the same gas station, I would change gas station.

Get a good scanner.

I would double check spark plugs. Make sure you got the correct spark plugs. Then would check the coils, oil change, pcv valve and catch-can (if you have one). You can do all those things. Next would be injectors.

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[jp1234]

Same gas in the tank? If you already put more gas from the same gas station, I would change gas station.

Get a good scanner.

I would double check spark plugs. Make sure you got the correct spark plugs. Then would check the coils, oil change, pcv valve and catch-can (if you have one). You can do all those things. Next would be injectors.

I went to a different gas station then the one I did last time, I'll check all of that tomorrow and report back, a friend suggested I reset the PCM and see if that will fix it aswell

 

[Cobra Jet]

A misfire can be caused by a lot of things - and not every misfire is detrimental.

Just in general, there are many things known to cause common Coyote P0300 misfires. UNLESS there is a specific DTC thrown, some misfires are sporadic and a code isn't always captured. Even a general P0300 misfire code is too general and will send you and a Tech on a witch hunt.

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/

However, here's some things you can check:

Check the connector at the MAF and make sure it's totally secured. Make sure you don't have any breaches along the air intake track, or any cracks damages to the intake. Any such breach before or after the MAF is a vacuum issue and will skew signals for incoming air flow monitoring.

---
Pull the plugs and post images of what you find for their readings/condition.

---

- VCT solenoids - if the solenoids are not operating properly due to debris or they are failing due to age, they can cause such codes. Quite a few threads on here about these prematurely failing and/or how to diagnose.

The culprit here was the VCT solenoid::
https://www.mustang6g.com/forums/th...s-and-cam-retarded-codes.176734/#post-3571964

Here's (2) more threads for VCT info that I had previously posted in other threads:
https://www.mustang6g.com/forums/threads/2015-2021-s550-5-0’s-ssm-50067-vct’s-again-various-dtc-codes.169419/

https://www.mustang6g.com/forums/threads/p0018-code.123932/

- Crank sensor - failure can be the sensor itself, the harness to it or the pins in the connector. If the crank sensor is failing, it also will throw various misfire DTCs. The only time the crank sensor will throw a specific crank DTC is if the sensor is disconnected or it has completely failed. Many have found even with a generic misfire P0300, that the issue was related to the crank sensor. These sensors do not last forever due to their location and under hood heat cycles.
Check this thread:
https://www.mustang6g.com/forums/threads/misfire-at-high-rpm.174380/#post-3531453

AND this one:
https://www.mustang6g.com/forums/th...e-sensor-tone-ring.156234/page-2#post-3197692

The IMRC design has been problematic since the IMRC intake system first debuted in the 1994 Lincoln MKVIII with the 4.6 DOHC (which was then carried into the 1996 Cobra and beyond). Theres MANY threads on here regarding the intake and IMRC system.
https://www.mustang6g.com/forums/threads/possibly-broken-imrc-shaft.183221/#post-3689879

—

Ignition coils:
If you’re getting a common or steady P030x (specific cylinder) then it could be a failing ignition coil pack. To determine this, if you have a P0304 for example, swap the Cyl 3 and Cyl 4 ignition coils - see if you now get a P0303 instead of a P0304…. If you do, it’s a faulty coil pack.

 

[jp1234]

A misfire can be caused by a lot of things - and not every misfire is detrimental.

Just in general, there are many things known to cause common Coyote P0300 misfires. UNLESS there is a specific DTC thrown, some misfires are sporadic and a code isn't always captured. Even a general P0300 misfire code is too general and will send you and a Tech on a witch hunt.

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/

However, here's some things you can check:

Check the connector at the MAF and make sure it's totally secured. Make sure you don't have any breaches along the air intake track, or any cracks damages to the intake. Any such breach before or after the MAF is a vacuum issue and will skew signals for incoming air flow monitoring.

---
Pull the plugs and post images of what you find for their readings/condition.

---

- VCT solenoids - if the solenoids are not operating properly due to debris or they are failing due to age, they can cause such codes. Quite a few threads on here about these prematurely failing and/or how to diagnose.

The culprit here was the VCT solenoid::
https://www.mustang6g.com/forums/th...s-and-cam-retarded-codes.176734/#post-3571964

Here's (2) more threads for VCT info that I had previously posted in other threads:
https://www.mustang6g.com/forums/threads/2015-2021-s550-5-0’s-ssm-50067-vct’s-again-various-dtc-codes.169419/

https://www.mustang6g.com/forums/threads/p0018-code.123932/

- Crank sensor - failure can be the sensor itself, the harness to it or the pins in the connector. If the crank sensor is failing, it also will throw various misfire DTCs. The only time the crank sensor will throw a specific crank DTC is if the sensor is disconnected or it has completely failed. Many have found even with a generic misfire P0300, that the issue was related to the crank sensor. These sensors do not last forever due to their location and under hood heat cycles.
Check this thread:
https://www.mustang6g.com/forums/threads/misfire-at-high-rpm.174380/#post-3531453

AND this one:
https://www.mustang6g.com/forums/th...e-sensor-tone-ring.156234/page-2#post-3197692

The IMRC design has been problematic since the IMRC intake system first debuted in the 1994 Lincoln MKVIII with the 4.6 DOHC (which was then carried into the 1996 Cobra and beyond). Theres MANY threads on here regarding the intake and IMRC system.
https://www.mustang6g.com/forums/threads/possibly-broken-imrc-shaft.183221/#post-3689879

—

Ignition coils:
If you’re getting a common or steady P030x (specific cylinder) then it could be a failing ignition coil pack. To determine this, if you have a P0304 for example, swap the Cyl 3 and Cyl 4 ignition coils - see if you now get a P0303 instead of a P0304…. If you do, it’s a faulty coil pack.

Wow that's alot of information I appreciate it man, so far today I've gone through the plugs, and checked all of them (I forgot to take pictures) they all looked pretty clean like you'd think 1000mile plugs would look like. I checked over all my connections and found that my positive terminal clamp was super loose and barely making a connection so much so it came off when I went to the store today also found it was cracked so I bought a replacement, would that have any effects on the misfire? Ive found the mis and flashing cel happen in 4th gear at around 3k rpm whenever I get into it a bit. So far I've cleaned maf and throttle body, and put injector cleaner in my gas tank. Hoping one of these will solve my issue

 

[Cobra Jet]

Wow that's alot of information I appreciate it man, so far today I've gone through the plugs, and checked all of them (I forgot to take pictures) they all looked pretty clean like you'd think 1000mile plugs would look like. I checked over all my connections and found that my positive terminal clamp was super loose and barely making a connection so much so it came off when I went to the store today also found it was cracked so I bought a replacement, would that have any effects on the misfire? Ive found the mis and flashing cel happen in 4th gear at around 3k rpm whenever I get into it a bit. So far I've cleaned maf and throttle body, and put injector cleaner in my gas tank. Hoping one of these will solve my issue

A bad battery cable could cause all sorts of weird stuff.

Definitely replace it because these S550 battery cables are known to become corroded at the terminal. However what most people don’t realize is the corrosion wicks up the cable strands into the cable beyond the terminal connection. So you’re good if you’re replacing the length of cable for sure.

 

[jp1234]

A bad battery cable could cause all sorts of weird stuff.

Definitely replace it because these S550 battery cables are known to become corroded at the terminal. However what most people don’t realize is the corrosion wicks up the cable strands into the cable beyond the terminal connection. So you’re good if you’re replacing the length of cable for sure.

I poured some coke on it to clean up the corrosion lol then replaced the clamp, Currently driving around to get the injector cleaner I put in cycled through. But idle has definitely gotten worse then it was this morning

 

[Kabayo]

Double check the plugs. Mark and move those coils to different cylinders. Also you can turn on the engine and unplug 1 coil at a time and see if there's a change on the idle.

Agree with double checking the plugs…pregaped

Double check the plugs. Mark and move those coils to different cylinders. Also you can turn on the engine and unplug 1 coil at a time and see if there's a change on the idle.

Agree with double checking the plugs…pre gapped by Ford means nothing.

 

[jp1234]

Update, so I've pulled the injectors, visually inspected them, and cleaned them up a bit they didn't look to bad. I've checked the plugs again. And I swapped all of the coils out with good ones from a buddies s550. Ive also done a pcm reset and went through that. Misfire codes are still flashing when I get on it in 4th gear at same rpm range and I'm also having alot of backfires in every gear. my buddy pointed out he could smell rotten eggs like bad cats after the pull. I don't really know where to go from here other than pulling the intake manifold and checking the crank sensor

 

[jp1234]

just to see if i can revive this thread, I went and took the car to ford, they told me the spark plugs needed to be changed, i let them know that they were changed around 1000 miles ago and they still told me that was the issue, i got the car back and bought some ngk plugs for the car and put them in made sure the gap was right. The problem was gone and the car pulled like it should with no misfires no nothing. the smell in 4th still persists but i wrote that off as the cats getting hot at high rpm in 4th, thinking the problem was solved i went and got the car tuned by lund this was about 1000miles after i changed to the ngk plugs. during the tuning log process the flashing cel came back and i was able to get it in the log. i told lund they just told me to do a crankrelearn and that everything looked fine. i did the relearn and it did not solve the issue. i have since had the flashin cel come on multiple times since then, and i dont know if its related or not but around the same time the cel came back the ac compressor now ticks rapidly when turned on

 

[Vtown702]

just to see if i can revive this thread, I went and took the car to ford, they told me the spark plugs needed to be changed, i let them know that they were changed around 1000 miles ago and they still told me that was the issue, i got the car back and bought some ngk plugs for the car and put them in made sure the gap was right. The problem was gone and the car pulled like it should with no misfires no nothing. the smell in 4th still persists but i wrote that off as the cats getting hot at high rpm in 4th, thinking the problem was solved i went and got the car tuned by lund this was about 1000miles after i changed to the ngk plugs. during the tuning log process the flashing cel came back and i was able to get it in the log. i told lund they just told me to do a crankrelearn and that everything looked fine. i did the relearn and it did not solve the issue. i have since had the flashin cel come on multiple times since then, and i dont know if its related or not but around the same time the cel came back the ac compressor now ticks rapidly when turned on

I have the same problem with my 2017 gt. Just replace the trans and clutch. Was getting misfire codes. Did a crank relearn took care of those. But I also have an issue in 4th gear just rolling into the throttle will not rev past 3 thousand. But if I’m in the rpm from third to 4 it will cont to pull. But not when I just roll into it. Going to swap intakes next for an 18. Thinking my imrc flaps are broken. Hope we can both get some answers

 

[jp1234]

I have the same problem with my 2017 gt. Just replace the trans and clutch. Was getting misfire codes. Did a crank relearn took care of those. But I also have an issue in 4th gear just rolling into the throttle will not rev past 3 thousand. But if I’m in the rpm from third to 4 it will cont to pull. But not when I just roll into it. Going to swap intakes next for an 18. Thinking my imrc flaps are broken. Hope we can both get some answers

Yeah that is odd, I think I was able to fix mine fingers crossed. My voltage would drop down to like 10.3 cruising and I think my sub was pulling too much power causing my misfires. I've sinced removed the amp and sub and i haven't had it throw any codes but my idle is still kinda rough imo

 

[HKusp]

Update, so I've pulled the injectors, visually inspected them, and cleaned them up a bit they didn't look to bad. I've checked the plugs again. And I swapped all of the coils out with good ones from a buddies s550. Ive also done a pcm reset and went through that. Misfire codes are still flashing when I get on it in 4th gear at same rpm range and I'm also having alot of backfires in every gear. my buddy pointed out he could smell rotten eggs like bad cats after the pull. I don't really know where to go from here other than pulling the intake manifold and checking the crank sensor

Check to see if your cats are coming apart. @NGOT8R had a cat come apart and it can cause a lot of issues. Hopefully he'll chime in.

 

[jp1234]

Check to see if your cats are coming apart. @NGOT8R had a cat come apart and it can cause a lot of issues. Hopefully he'll chime in.

I was also thinking something might be wrong with the cats and was planning on just installing bluetooth cats lol

 

[NGOT8R]

Yes, definitely check your cats. Here’s what happened to mine.

https://www.mustang6g.com/forums/th...t-failure-and-broken-weld-on-mid-pipe.191891/

https://www.mustang6g.com/forums/threads/2019-bullitt-fuel-line-leak.197116/#post-4026028

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