P303 good coil pack, good plugs, new injector, and good compression

[Corysf62]

Good evening.

I have a question that’s probably been addressed before as I know I’ve been reading about the Hemi tick.

Before I go down a rabbit hole I don’t really want to, I want to know how or if I can determine if this is my problem.

2014 Ran 1500, 5.7 Hemi, 98k.

I am getting P303.

I replaced all the coil packs and all the spark plugs just because 98k miles and I thought this was going to be my issue as I never really hear a tick, and didn’t learn about that until I started with all this.

I still had the code, so I also replaced the fuel injector for #3

I still am getting P303, and just to clarify, I have OBD2 device and yes u cleared codes after each step.

I pulled 1 plug on #3 and did compression test, getting 150ish and it holds without dropping until I press the release.

And to rule out any issue with bad replacements, I swapped coil packs and plugs with #2 and problem stays with #3

I saw something about maybe a lifter spring as opposed to the cam shaft, but I don’t want to just start chasing the rabbit…

Thanks in advance

 

[Wild one]

Good evening.

I have a question that’s probably been addressed before as I know I’ve been reading about the Hemi tick.

Before I go down a rabbit hole I don’t really want to, I want to know how or if I can determine if this is my problem.

2014 Ran 1500, 5.7 Hemi, 98k.

I am getting P303.

I replaced all the coil packs and all the spark plugs just because 98k miles and I thought this was going to be my issue as I never really hear a tick, and didn’t learn about that until I started with all this.

I still had the code, so I also replaced the fuel injector for #3

I still am getting P303, and just to clarify, I have OBD2 device and yes u cleared codes after each step.

I pulled 1 plug on #3 and did compression test, getting 150ish and it holds without dropping until I press the release.

And to rule out any issue with bad replacements, I swapped coil packs and plugs with #2 and problem stays with #3

I saw something about maybe a lifter spring as opposed to the cam shaft, but I don’t want to just start chasing the rabbit…

Thanks in advance

Pull the drivers side valve cover and see if all the rocker arms are moving the same amount when you turn it over,you can also check the valve springs over.

 

[Burla]

Sometimes cam lobs fail gently and slowly, usually when this happens you generally can avoid a mis fire when cold and oil is thick. So early cam fails like before the lob is totally gone can fool a compression test. So you did compression tests on multiple cylinders and 3 was equal? Anyhow, like rick said take off covers, but just because you passed a compression test doesn't necessarily mean you escaped a cam lob.