Check engine light came on this morning so I took truck in to Autozone for a quick scan and got the above message.

On the emailed report it says "not able to identify a fix" but on the printout the recommended fix is "reprogram powertrain control module (PCM)".

Is anyone familiar with this? Really hoping it's nothing serious engine-wise.

Could be a lot of things. Ignition coil, spark plugs, fuel pressure, vacuum leak.

Uh oh. Not good. That will be an engine rebuild. Might as well sell it to me cheap….

Probably an ignition coil as mentioned above but could be something else.

If it were a specific coil, it would probably also throw a P030X (x = cylinder misfiring) if I understand it correctly.

P0300 is random so i'd be looking system-wide. EGR, O2 sensor, vacuum leak. Are you noticing the engine stumble, have trouble starting, or is down on power on the freeway?

Does the exhaust smell like rotten eggs?

When is the last time you changed spark plugs/coils/etc?

Spark plugs and O2 sensors are relatively cheap, I would start there.

Just read about a service bulletin that mentioned bad contact on Fuse 27 causing a DTC code? idk but might be worth also checking it out, removing the fuse, cleaning contact, etc.

Flaith said:

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If it were a specific coil, it would probably also throw a P030X (x = cylinder misfiring) if I understand it correctly.

P0300 is random so i'd be looking system-wide. EGR, O2 sensor, vacuum leak. Are you noticing the engine stumble, have trouble starting, or is down on power on the freeway?

Does the exhaust smell like rotten eggs?

When is the last time you changed spark plugs/coils/etc?

Spark plugs and O2 sensors are relatively cheap, I would start there.

Just read about a service bulletin that mentioned bad contact on Fuse 27 causing a DTC code? idk but might be worth also checking it out, removing the fuse, cleaning contact, etc.

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I have heard spark plugs are a b**** to change on these trucks and unfortunately am not the most handy, outside of the basic stuff.

Yesterday morning I do think it was driving a little weird and down on power on the freeway, but then again, the wind was pretty crazy from the front and it could have been in my head.

Haven't noticed any weird smell of exhaust. The truck has always made kind of weird noises (sometimes rattling/gravely sound) at lower speed and RPM, but every F-150 forum seems to say this is "normal". I have always wondered if the occasional rattling/marbles sound at lower speed acceleration could possibly be from the 87 octane.

Love the truck overall, but it hasn't been the smoothest/quietest ride I have ever experienced. Going to take it in to a shop near me I think. Was just hoping maybe it could be something that just needs to be reset.

Mustang has an intermittent P0301.

On the coyote there are vacuum actuated flaps in the intake. One reason a P0300 will show up is if the actuator rod for those flaps is broken.

BG Knocc Out said:

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Check engine light came on this morning so I took truck in to Autozone for a quick scan and got the above message.

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Did Autozone erase the code and turn off the light for you?

If 'yes', has the light come back on and are you noticing any stumbling or other driveability issues?

A 'random' could be as simple as a dirty fuel filter.

Ribeye-Rare said:

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BG Knocc Out said:

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Check engine light came on this morning so I took truck in to Autozone for a quick scan and got the above message.

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Did Autozone erase the code and turn off the light for you?

If 'yes', has the light come back on and are you noticing any stumbling or other driveability issues?

A 'random' could be as simple as a dirty fuel filter.

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The light actually went off the next day. Truck seems to be running fine. I will never understand these modern vehicles. It's like sometimes there are just random electronic/chip glitches that just need to be reset on their own or something.

My light went out as well.

Have new injectors, haven't R&Red yet.

Still feel a stumble at idle.

https://static.nhtsa.gov/odi/tsbs/2018/MC-10136581-9999.pdf

the TSB is just to reprogram the PCM. i'd check if this applies

My 2018 5.0 F150 has a misfire under load.
Cylinder 6 and 8 are both missfiring. I've replaced the spark plugs and moved the coil packs from working cylinders to bad cylinders. Recently I replaced the two direct injectors for cylinder 6 & 8. Missfire continued. I'm not sure what to do from here. Compression issue?

Rdearcos8 said:

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My 2018 5.0 F150 has a misfire under load.
Cylinder 6 and 8 are both missfiring. I've replaced the spark plugs and moved the coil packs from working cylinders to bad cylinders. Recently I replaced the two direct injectors for cylinder 6 & 8. Missfire continued. I'm not sure what to do from here. Compression issue?

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Run a cylinder leak-down test.

Kenneth_2003 said:

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Rdearcos8 said:

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My 2018 5.0 F150 has a misfire under load.
Cylinder 6 and 8 are both missfiring. I've replaced the spark plugs and moved the coil packs from working cylinders to bad cylinders. Recently I replaced the two direct injectors for cylinder 6 & 8. Missfire continued. I'm not sure what to do from here. Compression issue?

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Run a cylinder leak-down test.

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This is what the dealer tested when I had the same situation on my 2018. I had a missfire after new plugs and coils. Turned out to be low compression on two cylinders and I needed a new long block.

I hope it's not that serious.

I just passed a 100,000 miles on my 5.0 2018 F150. I replaced the spark plugs at 75,000.

Other than that I replaced the starter around 40,000 miles that was faulty.

Currently, I just noticed a couple of days ago the two USB ports at the bottom near floor level below the radio wasn't working. I tried multiple cables, but it doesn't work.

I guess I need to order new USB ports, and see if I can swap it out.

TSJ said:

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Kenneth_2003 said:

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Rdearcos8 said:

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My 2018 5.0 F150 has a misfire under load.
Cylinder 6 and 8 are both missfiring. I've replaced the spark plugs and moved the coil packs from working cylinders to bad cylinders. Recently I replaced the two direct injectors for cylinder 6 & 8. Missfire continued. I'm not sure what to do from here. Compression issue?

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Run a cylinder leak-down test.

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This is what the dealer tested when I had the same situation on my 2018. I had a missfire after new plugs and coils. Turned out to be low compression on two cylinders and I needed a new long block.

I hope it's not that serious.

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I had a burned valve on my 2014 5.0 last November. Had a CEL come one a week before going in for a State Inspection which I obviously failed. P307, cylinder 7 misfire. They checked the (relatively) newish plug then played swap the coils around, all without success. 7 was routinely missing and showed up plainly on the power balance. Hooked up the cylinder leak down and a rubber glove on the exhaust pipe was waving to the crowd.

Ended up having both heads sent off for machining. Because you have to nearly fully disassemble the drivers side to get to the passenger side, and everything is sold in a full matching pair. So full timing job (you've already torn the whole thing apart), cooling system drain and fill, the cams were still good, 32 new valves and springs etc.

All in $7800...

I found and fixed the Issue!!!!!

I brought my truck into work at my shop and pulled the Y-pipe and both of my catalytic convertors were severely clogged.
I didn't want to pay $3500 to get new cats installed so I gutted those mf's out.
I kept the Oxygen sensors in and reinstalled the Y-Pipe and started it up and that thing roared.

Anyways... Missfire gone, car idles smoothly and rips. Thank you all for your help, I am beyond lucky that it wasn't worse than what it was.

Edit: (I also live in Florida and have no state ref/emissions)