P0300 random misfire — 2022 Mach 1 5.0

[Chip]

Hey guys, I just bought a 2022 Mustang Mach 1 with 25k miles last week.

Tonight I filled up with 93 at 7-Eleven. Right after leaving the gas station, I accelerated at maybe 40% throttle and the check-engine light started flashing for about 10 seconds then completely went away. The car has been running normally since.
I went straight to O’Reilly and they pulled P0300 — Random Misfire Detected.
There’s also a recall on this Ford 25S75 / NHTSA 25V455 low-pressure fuel-pump recall (software update)
Has anyone with a 2021–2022 5.0/Mach 1 experienced this? Could the fuel-pump recall be related to the P0300, or should I be looking more at plugs/coils or possibly bad fuel?
I’m taking it to Ford tomorrow, but I’m curious what ended up being the cause for anyone who had the same issue.Thank you!

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[allfivefifty]

Yeah your hunch might be correct. I would put a bottle of Chevron Tecrhon and run that. Could be a bad fuel batch. Fill up with top tier gas (ExxonMobil shell Costco) and avoid the non top tier fuel if you can.

 

[Craig Brown]

Yes, fuel pressure fluctuations can cause a random misfire. I bought a fuel line adapter off e-bay (UPR fuel line adapter) and a fuel pressure gauge (0 - 100Lbs oil filled) and mounted it to the fuel line and did a fuel rail pressure test and that will tell you if your pump is functioning correctly or not. The cost was $63.00 for the two items. It will let you know if your fuel delivery module, fuel pump back check valve, fuel pump pressure, are correct and working, you can tell if you have any injectors leaking down after the car is turned off. I found it to be a very useful tool.

 

[Epiphany]

Mode 6 in FORScan will tell you which cylinders are misfiring and at what rate.

 

[allfivefifty]

Mode 6 in FORScan will tell you which cylinders are misfiring and at what rate.

If it's a particular cylinder wouldn't you get P030X, where X is the cylinder number? I have seen that before.

 

[Whitedevil95]

I have a 2022 Mach 1 and my Ford pass doesnt show any recalls for me.

 

[Pistol_91]

I just recently started my car with a half dead battery and it threw a misfire code. Treat it like a 2 stroke weed whacker. Once you start it rev the piss out of it and it'll wake it up

 

[Craig Brown]

Just because you get a code doesn't mean you have a misfire. If you have a real cylinder misfire you will feel it. PO300 is a random misfire code and that can be caused by anything from low battery voltage to a small vacuum leak and still never produce an actual cylinder misfire. Even a dirty injector that is slow to respond can set off that code and still not have a real misfire. But yes, a scan tool can help you pinpoint your issue.

 

[Epiphany]

If it's a particular cylinder wouldn't you get P030X, where X is the cylinder number? I have seen that before.

Can't speak to that other than I've seen misfires with codes or no codes that are logged in Mode 6 or in HP Tuners scanner software.

If you have a real cylinder misfire you will feel it. PO300 is a random misfire code and that can be caused by anything from low battery voltage to a small vacuum leak and still never produce an actual cylinder misfire. Even a dirty injector that is slow to respond can set off that code and still not have a real misfire.

All true.

 

[BullittTheBlueSky]

I just recently started my car with a half dead battery and it threw a misfire code. Treat it like a 2 stroke weed whacker. Once you start it rev the piss out of it and it'll wake it up

Oh good Lord don't do this. This is absolutely terrible advice.

You may want to destroy your engine, but don't try to convince others to do the same.

 

[Skye]

Welcome to the Forums.

When studying something like this, I want to be able to repeat the issue, or, determine under what conditions it's most likely to occur. I want to gather as much insight before t-shooting or considering any changes.

New to you car. We don't know what brand of fuel or octane was used previously. It's been re-filled with 7-Eleven gas. The misfire event has happened once thus far.

Consider when the event occurred. You stopped for fuel. It'd been sitting without any airflow going across the car, through the engine and the radiator. I'm often at 220 F / 104 C after a re-fuel, when I typically run in the 190s / 80s. I've always started off and driven somewhat gently, until temps are back to their typical operating range.

Unknown fuel history + 7-Eleven gas + hot temps after re-fuel = optimum environment for misfire.

Enjoy the car. Every 1/4 tank or so, re-up with a Top Tier fuel, highest octane you can find.

https://www.toptiergas.com/

In the mean time, continue to monitor the situation. Once you've 1/4 re-upped a few times, adding one bottle of Techron wouldn't hurt. A run on the highway (50 miles?) after adding the Techron would help. Something sustained for a bit. No need to immediately drain the tank.

If you later continue to experience the issue, you could try some of the suggestions to help isolate the problem.

I don't believe the recall is influencing this. 25S75 involved conditions and instances where the fuel pump would fail, stalling a vehicle. Details on that follow.

https://www.mustang6g.com/forums/th...-nhtsa-low-pressure-fuel-pump-failure.218415/

The fix for this recall is a Powertrain Control Module re-flash. This can be done at the dealer or via Ford's mobile service. Takes about one hour.

But yes, have any and all recalls cleared.

Edit,

If you're not already familiar with Ford's products, there's a tool which will help you pour in the Techron.

Inside Ford's filler neck are a series of flaps; their (and other pieces) primary purpose is to prevent fuel loss in the event of a rollover. They also help prevent theft or people from inserting the wrong type of fuel.

When adding liquids from a can, you'll need to get past the flaps.

1. Open the trunk.

2. Remove the felt facade covering the air pump.

3. Look to the left for something white.

There should be a small, white funnel clipped to the unibody. Before adding the Techron, insert the funnel. If the funnel is not there, it might be in the glove box. These small funnels can be purchased in parts stores .

 

[Pistol_91]

Oh good Lord don't do this. This is absolutely terrible advice.

You may want to destroy your engine, but don't try to convince others to do the same.

If you consider that "convincing" you must be easy to persuade.

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