Negative Fuel Trims No CEL
 

Hey guys,

I searched the forum and found a few posts with similar problems, but nothing that replicates my issues.

I have a 2013 BRZ 50k miles. JRSC C38 kit, 2017 intake manifold, Openflash Headers, Invidia OP, Catless resonated front pipe, q300 Catback and OFT tuned by Shiv.

The tune has worked well for a few months until I recently noticed a loss of power. I have not experienced any CEL codes however the engine does sound raspier.

At Idle my fuel trims are normal however they get increasingly negative under load. It used to be -10 and has been steadily increasing to a now - 20.

My data logs can be found here:

http://www.datazap.me/u/njmaske/commute?log=0&data=1-12
http://www.datazap.me/u/njmaske/log-...=0&data=1-4-12
http://www.datazap.me/u/njmaske/log-...og=1&data=1-12

Possible issues
1) Maf (cleaned using maf cleaner, checked o-ring seal
2) Bad 02 Sensor (not sure how to diagnose this)
3) Stuck open fuel injector (not sure how to diagnose this)
4) Direct injector seal (I am not getting any intake popping
5) Bad spark plugs (not getting any missfire codes, not sure if this will cause codes)
6) Vacuum Looks OK
7) Boost Looks OK

I am seeing a correlation on the commute log between fuel rail pressure and fuel trims leading me to believe its a stuck injector, However I no expert.

Any help would be appreciated in diagnosing this issue.

Anyone?