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

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