CEL!!!
 

My check engine light came on, took it to the subaru dealer to diagnose, and it ended up being a code for running too lean and the "fuel rail?". I have a borla cat-back exhaust and a custom intake (basically K&N). The guy who made the intake said that he's had the issue with it being too lean on BRZ's only in the past. Said the fix is a smaller diameter pipe (not sure how that works if someone could explain that would be great...) whereas the subaru dealer (as usual) said the fix is to take of the CAI. The subaru mechanic tried to explain the issue as the radiator fan was forcing extra air into the intake causing it to run lean.. :bonk::bonk: So you can see where I would take his "expertise" with a grain of salt.

Mainly I would just like to know if anyone has prior experience with this code and also if anyone that knows more about cars could explain the issue with the different diameter CAI pipes. :iono:

Thanks!

If your custom intake piping is a different diameter than stock where the MAF sensor is located then it will throw off your fueling, calculated engine load, etc.

You need to re-scale the MAF if the piping diameter is different.

That is a likely cause for your too lean code.

The new pipe will be the same diameter of the perrin intake. Judging by the looks of the perrin and mine, the MAF sensor looks to be in the same place almost so hopefully this will work.