WOT stumble/lean


New member
Hello, I stumbled across this site searching for answers.. I saw someone who posted an issue similar to this in 2014, a fuel pump solved his issues. I believe mine is some other gremlin in the system. I have a 2005 Subaru WRX with an EJ257 IAG stage 2 block, FP blue turbo, 1100cc FIC injectors, AEM 340lph pump, and many more upgrades.. still stock fuel tree..

Car was professionally tuned by Calvin @ Dotson tuning.. she was tuned well and this issues are recent.. I have changed the MAP sensor with a 4bar COBB MAP which she was originally tuned on, the fuel pump is only a year or two old, and she is a weekend driver.. not many miles on the pump. Normal driving conditions she runs fine.. I can even get into throttle.. 80% and she pulls hard and accelerates.. tuned to produce 21psi of boost. Under WOT she stumbles pretty much the whole way up after 4k. If I stay in it, she gives me a flashing CEL which goes away after a few sec under normal driving. the data log reads 11.25 AFR after I've been in the throttle for less than a sec. at at 4500rpm..ish the most boost she gives me is 19.36.. of course I do not push her as she has a fit. I don't believe there is any boost/vacuum leaks. she runs e85 so the lines should be clean. I am open to any suggestions, comments, advice. Anything.


I sent a data log to a friend of mine that tinkers.. he has a program he placed the data log in and sent me this

this is a link to a google drive that has the whole data log.. the actual pull is at cell 2230 (it opens for me in an EXCEL format)