P0303 - Issue Hunting

[pojie_19]

Howdy all
2019 Laramie 5.7 4x4, no etorque
58k miles
Truck lost power and started violently shaking while driving yesterday. CEL flashes then goes solid. Very jerky while driving in reverse.
Had the code pulled by AutoZone, P0303 for cylinder 3 misfire. Pulled up a layout on my phone that showed driver side bank as odd number cylinders, cylinder 3 is the 2nd from the front on the driver side. Swapped the coil packs on cylinders 2 and 3 to see if it changed the code, code is still showing for cylinder 3 misfire. Also replaced the spark plugs while I was in there.

Next thing I can think to check is the injectors. Does anyone have an easy way to check these without just straight up replacing them.

I've also seen a couple threads where the wiring harness is the issue, I live in the country and mice cause problems sometimes. Is there a "baseline" voltage I should see if I unplug the coil pack and put a meter on the plug (truck side not coil side).

Also want to confirm that the engine is laid out odd cylinders on the driver side and even cylinders on the passenger side. My Ford was sequential with 1-4 on the driver and 5-8 on the passenger. I'd hate to be chasing this issue still because I changed the wrong coil pack!

 

[shlunky]

Not sure if you still have this issue or not, but I too had this happen some months ago.

Turned out to be a faulty injector.

 

[theblet]

Found this on another forum

 

[HSKR R/T]

Howdy all
2019 Laramie 5.7 4x4, no etorque
58k miles
Truck lost power and started violently shaking while driving yesterday. CEL flashes then goes solid. Very jerky while driving in reverse.
Had the code pulled by AutoZone, P0303 for cylinder 3 misfire. Pulled up a layout on my phone that showed driver side bank as odd number cylinders, cylinder 3 is the 2nd from the front on the driver side. Swapped the coil packs on cylinders 2 and 3 to see if it changed the code, code is still showing for cylinder 3 misfire. Also replaced the spark plugs while I was in there.

Next thing I can think to check is the injectors. Does anyone have an easy way to check these without just straight up replacing them.

I've also seen a couple threads where the wiring harness is the issue, I live in the country and mice cause problems sometimes. Is there a "baseline" voltage I should see if I unplug the coil pack and put a meter on the plug (truck side not coil side).

Also want to confirm that the engine is laid out odd cylinders on the driver side and even cylinders on the passenger side. My Ford was sequential with 1-4 on the driver and 5-8 on the passenger. I'd hate to be chasing this issue still because I changed the wrong coil pack!

Swap injectors from bank one to bank two and see if code follows. Bank one is drivers side, odd number cylinders. Bank twonis passenger side, even number cylinders. Ford is weird. Chevy and Mopar small blocks have always been odd number drivers side, even number passenger side with 18436572 firing order.