Hello everyone. New here!

So I've had a very pesky time with check engine code P2178 on a 2008 C30 - T5 - R design

I've had it looked at by maybe 5 or 6 mechanics for two years, spent arpund 2 thousand in repairs and still this light comes back after it goes away for months. I'm starting to think the mechanics I've gone to (Even euro specialists) simply don't know how to fix this code specifically on a Volvo C30.

I've had the MAF sensor replaced, O2 sensor replaced, also small vacuum leaks fixed, air filter changed, throttle body cleaned, cabin air filter changed. I've never once heard a single back-fire from the engine fortunately as this code means cylinder 1 is running too rich with fuel.

I've mentioned countless times to mechanics to just start with replacing the spark plug on cylinder 1 and the6 have all refused and said that isn't the problem. By process of elimination it seems that is a valid thing to try, and it's also much lower cost given it is the fix.

Lastly, my AC runs intermittently, it shuts off cool air eventually when AC button is engaged, especially in hotter weather. Not sure if that could be related as I haven't had that fixed yet.

I am curious if anyone has had this issue with their Volvo C30 or has heard of this before? It's reaching the point where I am considering selling the car because the repairs are too much for this error not being fixed, although everything is great with the car and I'd hate to sell it.

Perhaps it's just a computer read error?

Any advice would be super helpful!

-Anthony