Hi all,
I have benefited greatly from the content already, and wish I've had more time to dive into it before my own car issue popped up!
I have been troubleshooting this issue for a bit and I think a lot of what has happened over the past few months is related so i'll lay it all out. The original symptoms were loss of power with p0420 code, ended up being a clogged rear cat. I replaced this and drove great, but the front cat started to rattle so I replaced that as well. Started to make me suspicious that something was causing this upstream. After driving for a few weeks with no lights, p0302 came on for the first time. no real symptoms other than an occasional hesitation after hard acceleration. Idles great, responsive, nothing like that. I have swapped coils, plugs, and fuel injectors around and the code always stays on #2. one time I swapped the fuel injectors between #2 and #4 and oddly enough p0302 and p0304 came on, but p0303 went away on its own after driving for a bit. I brought it into the dealership for some diagnosing help but they didn't find anything, but it sounds like they didn't look that hard entirely since when I brought it in the code disappeared on its own only to come back a week later. They did verify the plugs (NGK) were gapped properly, and I did a crude spark test for each cylinder and verified there is spark. I hooked up a vacuum gauge and the need flutters as seen in the video below, and I can only think it has to be something with the valves or potentially HG since it does eat some coolant and oil, unsure of how much as it seems to have started more over the past few weeks. i'm new to this troubleshooting/diagnosing aspect as ive typically been a parts changer so all help/correction is appreciated!
Im planning on removing the heads next saturday and having a machine shop take a look, so would appreciate some confirmation im headed down the right path before I put all that work in. Thanks all!
-Noah
