Rep Power: 0

Hello so I have a 08 civic si with kseries fuel rail, stock injectors, Megan manifold, basic intake, walbro 255 fuel pump. I bought the car knowing it was running lean I replaced fuel sending unit and stock fuel pump and went to a 255 cuz that’s what I had laying around. That seemed to work for like 3-4 months no issues on a tune (in winter) then started to lean out again. In the beginning I could turn the car off and back on and that would fix it, now it’s doing it everyday. Afr is normal until 4,5k (vtech cracks) then shoots right up too 15-18. Just put a afr gauge in and also used Hondata app to make sure it wasn’t the sensor and everything matched between the two. Not really sure where to go from here. Any help would be greatly appreciated

 
Rep Power: 366

get it to a tuner and check the programming
running lean is what destroys engines, a tuner is less expensive

 
Rep Power: 221

Get a better tune

 
Rep Power: 0

tune is fine I ran it for at least 4 months and added a revision once it started leaning out and I have hondata too

 
Rep Power: 366

again, take to a tuner.
They probably will be able to tell you if something else is causing the issue.