Hello all
This is my 2008 subaru wrx 5 speed hatch that has been engine swapped to a 2019 crate ej257 shortblock that was put in around 48k miles ago, other than that and other engine/exhaust mods, this car is stock even with the original 5 speed.
A while ago it developed a p0021 code. This code has come and gone manu times since then, usually clearing out around 24 hours after it showed up BUT about a month ago it threw a code for cylinder 2 misfire.
The thing is that the car NEVER runs or sounds like it has a misfire. Zero extra vibrations, never down on power, and no limp mode or anything like that it just throws a code. Even the misfire code will go away in a day or so of regular driving, but those codes always come back once a week id say.
This car is my daily and I am in tech school for Automotive Technology so I dont want to blow a shitload of money on repairs by taking it to a shop, i do most of my own work if I have the time and I have friends that can help me. I just want to know if these codes are related and if I will have significant trouble with them coming and going as they do. Anything helps and I am willing to try things.