2004 with p0302 ( or not ? )

That'll help tell if they're firing. However, you'll need to remove them and take them in to see if there's an issue with clogging or dripping. That's where O'reilly can come in. I'd be leaning more towards dripping if the plug is wet.. assuming the compression test is good.

 

Gotcha I have a pending p0302 code right now, so first thing to do I think is go get a compression tool and check the compression. After that I can rule that out and move onto fuel injectors ? Or can faulty / clogged fuel Injector mess with compression ?

 

I wouldn't believe so. The system should still be sealed and the fuel rail pressurized. The compression test should indicate too much blow-by, a sticky valve, or worse, a blown head gasket. I don't think fuel injectors would affect that.

 

Gotcha, headed to the store to loan a tool, will update with numbers

 

I'm hoping for the best for you!

 

Just got the 4 coils and spark plugs out, I need to pull the efi fuse and relay from the fuse box in the engine bay before starting yes? Both or just the fuse ?

 

I would imagine just one would be fine

 

Disappointing results
1-180
2-90
3-180
4-170

What now :/

 

Do a leakdown test and see where its going (valves, rings, or head gasket)

 

Now to try and figure out if you have a head gasket or valve issue. A head gasket issue would usually contain other symptoms such as milky oil or low coolant.

 

I think a good place to start would be a leak down test as dm93 said

 

Yes, that can be a good indicator. I'm not sure but I believe you'll likely have to take it to a dealership or repair shop to have that done.

 

If you have an air source and a compression tester with a 1/4 npt fitting or quick connect you can do it yourself. Just take the shcrader valve out of the compression tester, roll the engine to tdc compression on the cylinder you want to test, screw your compression tester hose in and hook air to it.

 

Unfortunately just read that aswell that I need air source, don’t have a compressor available, unless I ask around. I have a few connections at local shops and what not so maybe I’ll ask around if anyone can do. Heard that local tuners usually do this type of thing?

 

Interesting. I recently got a p0304 code (cylinder 4 misfire). The truck would just run really bad at startup. So, I changed the spark plugs and replaced the coilpack with one from autozone's duralast brand. That was about 300 miles ago, and so far so good.

 

Thing is with the truck, it pulls decently , don’t really notice a loss of power , but it does shake / vibrate at idle

 

Yes that's what mine did as well, though I didn't drive it other than 10 yards until I fixed the problem

 

A cylinder with low compression will tend to miss at idle but be fine at higher speeds if it's not too low.

 

I see, I will try and find a shop that can help me do a leak down and hopefully that locates the issue, i will update as I learn anything new. If anyone has anything to add please let me know!

 

That can cause the code too. But it won't cause a compression issue which OP seems to have.