[Olson1288]

So I have an issue I've been chasing for a while now with no success. 2014 BRZ with a SBD turbo kit, car has around 100k miles and has had zero issues with the turbo kit being on for nearly 40k miles now.


I'm running into an issue where while driving, the car will stumble/surge pretty bad around 2.5-3k rpm. Vacuum/AFR's fluctuate hard while this happens, and seems to happen regardless of how light or heavy I am on the throttle. I am still able to drive the car carefully, but after around 10-15 minutes, the throttle almost stops responding completely, as if in limp mode. I was forced to pull over, and I was able to disconnect the battery and let the ECU reset, which allowed me to get it home (original issue still persisted however, just no more "limp mode").


The car has never once thrown any sort of CEL or any other light, even when the "limp mode" comes in, if that's what that was. Now the strange part, this only happens to me after driving somewhere and allowing the car to sit. I can start her up in the morning, drive 20 minutes to work or the gym and she will drive/pull perfectly. After sitting for 2 hours at the gym, the car will begin to stumble on the way home. Also, the car is able to idle perfectly, pulling normal vacuum + normal AFR's.


I have thoroughly checked for vacuum/boost leaks, cleaned the MAF, checked for any sort of injector or fuel leak, and I am honestly at a loss as to what is causing this issue, as it literally appeared out of nowhere. Car has been running perfect with the same tune for ~2 years, so I know it's not a tuning issue. I don't know if it could be an O2 sensor or something, but I would think the car would throw a code if that was the case. I plan to replace the MAF even though it has been cleaned and looks fine. I honestly don't know what else to do.


Also, it doesn't feel like a misfire, as I've dealt with that in the past. Car has aftermarket coil packs + OEM plugs that only have around 15k miles on them.



If anyone has any thoughts or ideas, anything else I could check, I'd truly appreciate it. I don't have much money to randomly throw at parts in an attempt to fix this unfortunately.