I purchased a 2018 5.0 10 speed sport package back in April of this year (2022) with about 54.5 k miles. I just hit 57k miles and was waiting for my next day off to do the oil change (6 days). During the 6 days I noticed the truck was idling rough and was shifting slow between 4-6 when accelerating from a dead stop and when coasting around in parking lots. Then my check engine light came on. I had the codes printed out at a auto parts store that stated the code was a P0300 I attached a photo of the print out. Anyone have suggestions?

 

I would start with changing the spark plugs. OEM

 

The codes;
300 is just a confirming code for misfires cylinders 1,2, and 4.
Codes 390, 394 are for the same issue detected. Bank 2 cam position detect failure.
390 is error, 394 is circuit intermittent.
Both are the failure of that function.
Treat these bank related codes as two different faults unless a wire harness is the cause.
They are on opposite banks.
Good luck.

 

I would not throw parts at it, bring it to a shop that can diagnose it and give you a repair estimate. If you want to fix it yourself at least then you will have a solid starting point. Was there a warranty from the dealer you bought it from or was it a private seller?

 

My guess is the misfires are a symptom of the cam position sensor issue. Bank 2 is cylinders 2, 4, 6, and 8, I think. Misfire on cylinder 1 is just possibly a side-effect of Bank 2 issues. Read https://www.obd-codes.com/p0394. It will give good discussion of troubleshooting. Good Luck (Look first for wiring/connector issues prior to firing parts cannon.) If this discussion is foreign to you take tltech recommendations in post 4.

 

Before one of the younger members corrects me! (I'm old school). Bank 1 is cylinders 1, 2, 3, and 4. (passenger side) and Bank 2 is cylinders 5, 6, 7, and 8. The link above (post 5) is still OK but agree with bluegrass. Issues are on opposite sides of engine!

 

I would put a lot of effort into the wire harness on this one as your mileage is not that high for a part's failure, but it still could be.
As for the trans skip shifting, this issue can cause the shift sked to change just the same as throttle applications do.
At low speeds and light throttle, you will have skip shifting as a normal function because it is load sensitive under light throttle application.
It's the attempt to save fuel at low speeds in a lot of stop and go when a lot of power is not needed to move the vehicle. The 5L has a lot of excess torque to play with.
.
I have an 18 with 67k that runs perfect and solving the oil passage issue plus engine noise is now at very low level.
Fuel mileage under controlled driving is well into the 22+ range.
Run a mix of E10/87 and E15/88 octane gas, Idle is smooth and does not lay down when power is needed. I cannot ask for more from this truck.
Good luck.