2015 Ford Mustang gt (p0300) engine misfire. !!!!!!UPDATE!!!!!!! More issues (p0300,p0316) HELP PLS

[Sean4m]

Hey guys another issue sadly so was driving the car check engine light came on and p0300 multiple engine misfires. I have new plugs in the car about a month old. I checked the plugs all looked fine and didn’t smell like gas so I don’t think I have a bad coil. I cleared the code and it came back on about a week later. Not sure what too do I have long tube headers coming next week with a appointment too put them in. Want too get the issue fixed ASAP any suggestions please post. I looked at other threads but all of their codes are associated with another code such as a cylinder specific misfire not sure what too do. Car runs and idles great and pulls strong.


!!!!!UPDATE!!!!

Hey guys been a while now have had zero issues with a misfire since until last night when I started my car. Drove home 15 minutes got a check engine light and sure engine got p0300 again, as-well as p0316 (misfire on startup within first 1000 revolutions). I am completely baffled, no one seems to know what the issue is, spark plugs are around 3 months old, stock injectors, stock ignition coils. Car runs great and drives fine can’t hear any audible misfires while driving. Oil pressure is great. I’m at the point where I’m going too start replacing ignition parts, plugs, coils, injectors. I am about too do a compression test as well. Tuner has looks at multiple logs at this point and he said he can’t see anything in the logs. Would love some help any ideas pls reply thank you!

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[npole]

Hey guys another issue sadly so was driving the car check engine light came on and p0300 multiple engine misfires. I have new plugs in the car about a month old. I checked the plugs all looked fine and didn’t smell like gas so I don’t think I have a bad coil. I cleared the code and it came back on about a week later. Not sure what too do I have long tube headers coming next week with a appointment too put them in. Want too get the issue fixed ASAP any suggestions please post. I looked at other threads but all of their codes are associated with another code such as a cylinder specific misfire not sure what too do.

I'm going with this by 1 year with no solutions (Bullitt), and I even had an engine swap between.
The shop tried to dismiss it initially with a "occasional bad fuel", while I always put in premium gas (that cost a tons here in EU) from different companies.
After one year they finally agreed that there's an issue, since they swapped the whole engine, they think it's something related to the coils (that haven't been changed with the engine, but the plugs only).
I've another (of countless) recovery next Monday for a full (remote) inspection with Ford factory, because the local shop is out of ideas.

 

[Sean4m]

I'm going with this by 1 year with no solutions (Bullitt), and I even had an engine swap between.
The shop tried to dismiss it initially with a "occasional bad fuel", while I always put in premium gas (that cost a tons here in EU) from different companies.
After one year they finally agreed that there's an issue, since they swapped the whole engine, they think it's something related to the coils (that haven't been changed with the engine, but the plugs only).
I've another (of countless) recovery next Monday for a full (remote) inspection with Ford factory, because the local shop is out of ideas.

Wow that’s really sucks, hope I’m never in your shoes. Will most likely buy a new set of coils and give them a shot and see if it fixes the issue. Also I emailed my tuner a log too see what he thinks. Best of luck with the car man hope you get her running perfect.

 

[npole]

As I mentioned in another thread, I've had so many problems with her in the first year than all the other cars I had in the past, summed together. I'm disappointed because I believed to have bought one of those american tanks that would run for hundred thousands miles without a single issue.. but obviously we aren't in the 70's anymore. While the platform is solid, a car nowadays isn't just an engine, it is surrounded by so much electronic, often provided by third party vendors that doesn't have any quality control in place up to the standards, ready to fail randomly.

As of your problem, if the error is about some specific cylinders, there's a good chance it's about the coils/cables serving those ones (as you already changed the spark plugs). If it's something happening on all cylinders randomly, the problem may lay somewhere else, as it's unlikely to have all the coils failing on you together.

In my case, the issues goes beyond this (and they might be related or not...), I smell that they will come back after the coils replacement as a "test", with: hey we gonna change the whole ECU, and so they swapped half of my car by then, to the point that would have been more convenient to offer me a brand new one. I may accept the offer to have a Mach1 with 0Km.

 

[Sean4m]

Gotchya I just used my friends obd2 reader and his said P0300, fuel level and fuel type need too be fixed I think I have a bad injector or got bad gas filled my tank about 3 days ago so am going too start there. Granny ku for the info.

 

[jackm415]

Got this code as well, took it to the dealer, and they figured it was the PCM had an issue. They reprogrammed it for <100$ total. They found nothing wrong with the engine (it was simply an electrical issue)

 

[MyStang]

Sean4m,
Just got the P0300,P0304 and P0308 codes all at once. Retrace what you did prior to getting the codes. For me, I just changed Oil/Filter and emptied my oil separator catch can. Passenger side PCV hose didn't click in the lock position and could've been causing a vacuum leak adding unmetered air to the system. As of now, no codes have returned.

 

[Sean4m]

Sean4m,
Just got the P0300,P0304 and P0308 codes all at once. Retrace what you did prior to getting the codes. For me, I just changed Oil/Filter and emptied my oil separator catch can. Passenger side PCV hose didn't click in the lock position and could've been causing a vacuum leak adding unmetered air to the system. As of now, no codes have returned.

I did exactly that, I work at a auto parts store and I had a customer come in and his car had the exact same issues as my car and the obd2 reader gave the same diagnosis and we found out that we both filled up at the same gas station. I went home and decided to siphon some gas out of my car and found a good amount of water in my gas. Cleared the code and put a heet gas treatment in with some good 93 octane gas, code hasn’t came back since. Hoping that was the issue.

 

[npole]

Mine has been recovered today, apart a similar issue above, it has "some" more. It will probably receive a new PCM, a new Audio Module.. and who know what else.
As I said, piece by piece, they are swapping the whole car... oh the seats are still original!

 

[Jackson1320]

Ok imrc’s can cause this. also a random multiple cylinder misfire code does not mean A random misfire. Just means that you have more than one cylinder misfiring And the misfire is not bad enough for the computer to determine the cylinders. It does not mean any random cylinder is misfiring

 

[Sean4m]

Ok imrc’s can cause this. also a random multiple cylinder misfire code does not mean A random misfire. Just means that you have more than one cylinder misfiring And the misfire is not bad enough for the computer to determine the cylinders. It does not mean any random cylinder is misfiring

i don’t have imrc’s, running a boss 302 mani. Has never came back after fuel treatment and good gas.

 

[Jackson1320]

I was giving a general answer for anyone having this problem not to any one person

 

[Sean4m]

Hey guys another issue sadly so was driving the car check engine light came on and p0300 multiple engine misfires. I have new plugs in the car about a month old. I checked the plugs all looked fine and didn’t smell like gas so I don’t think I have a bad coil. I cleared the code and it came back on about a week later. Not sure what too do I have long tube headers coming next week with a appointment too put them in. Want too get the issue fixed ASAP any suggestions please post. I looked at other threads but all of their codes are associated with another code such as a cylinder specific misfire not sure what too do. Car runs and idles great and pulls strong.

!!!!!UPDATE!!!!

Hey guys been a while now have had zero issues with a misfire since until last night when I started my car. Drove home 15 minutes got a check engine light and sure engine got p0300 again, as-well as p0316 (misfire on startup within first 1000 revolutions). I am completely baffled, no one seems to know what the issue is, spark plugs are around 3 months old, stock injectors, stock ignition coils. Car runs great and drives fine can’t hear any audible misfires while driving. Oil pressure is great. I’m at the point where I’m going too start replacing ignition parts, plugs, coils, injectors. I am about too do a compression test as well. Tuner has looks at multiple logs at this point and he said he can’t see anything in the logs. Would love some help any ideas pls reply thank you!

 

[npole]

!!!!!UPDATE!!!!

Hey guys been a while now have had zero issues with a misfire since until last night when I started my car. Drove home 15 minutes got a check engine light and sure engine got p0300 again, as-well as p0316 (misfire on startup within first 1000 revolutions). I am completely baffled, no one seems to know what the issue is, spark plugs are around 3 months old, stock injectors, stock ignition coils. Car runs great and drives fine can’t hear any audible misfires while driving. Oil pressure is great. I’m at the point where I’m going too start replacing ignition parts, plugs, coils, injectors. I am about too do a compression test as well. Tuner has looks at multiple logs at this point and he said he can’t see anything in the logs. Would love some help any ideas pls reply thank you!

Good luck with it.. Ford (not the local dealer, but the main factory) had my car running on their tests and determined that the vehicle has no issues, despite the fact that I have occasional misfires that are cutting the power, luckily it lasts less than a minute and the performance returns to the normality. For them everything is "normal", I dunno how it could be considered normal the engine light flashing and have the power cut down every couple of days, my logs are now filled with tens of these "errors", but that's what they said and released my car as perfectly healthy.

 

[Call_Me_Bruce]

!!!!!UPDATE!!!!

Hey guys been a while now have had zero issues with a misfire since until last night when I started my car. Drove home 15 minutes got a check engine light and sure engine got p0300 again, as-well as p0316 (misfire on startup within first 1000 revolutions). I am completely baffled, no one seems to know what the issue is, spark plugs are around 3 months old, stock injectors, stock ignition coils. Car runs great and drives fine can’t hear any audible misfires while driving. Oil pressure is great. I’m at the point where I’m going too start replacing ignition parts, plugs, coils, injectors. I am about too do a compression test as well. Tuner has looks at multiple logs at this point and he said he can’t see anything in the logs. Would love some help any ideas pls reply thank you!

Before firing the parts cannon, I'd suggest a proper diagnosis. Without a good scan tool, code set criteria, fuel pressure spec, wiring diagram, etc. an accurate internet diagnosis is a long shot at best. P0300 is a random misfire. Most likely Ford has a troubleshooting guide for P0300, if you can find that I'd start there. Not sure if Alldata would be helpful, may be worth it to subscribe. I see that you are in New York, not sure how far you are from Avoca, but if you are relatively close take it to South Main Auto, will save you time, money, and aggravation.

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