Fuel trims question ej205

Okay so this has been eating away at my brain for a couple weeks now, so much so that I am driving my beater.

When I drive my car hooked up to an OBD Reader & my Phone with torque, my LTFT averages at 3.9 or so, usually 6.9 at startup. My short term fuel trim is usually around 0 +- 8, but my app monitors HI - LOW sometimes it will max out at -25 and go as high as 18.X while driving, at idle on a cold start I have seen it go to -15. I have checked all air lines and there doesn't seem to be any post MAF leak, I have hooked up my air compressor to the Inlet and pressure tested at 10PSI all is well there.

what are my culprits most likely to be? is it a leaky/stuck open injector like I am thinking? I will be running some injector cleaner through and Visually inspecting them tomorrow in the sunshine.

Other issues could be Catless Exhaust.. Damage 02 sensor?

I am not getting any check engine lights, I thought -25 would throw a rich code? Can anyone else verify their Hi/ low STFT because from the guides I am reading online it should be -7 - +7 but it doesn't say anything about turbo cars. Vehicle has no drive ability issues maybe I am over thinking this.


Engine has 45K miles 03 Ej205 out of a wrx, 99 Legacy shell
it has ECUTEK tuning from I-Speed(now CrawfordPerformance)
full catless exhaust, 3 UP/DOWN 2.5Catback

*Screenshots tomorrow*

Thanks for any opinions or input. I just read Short term can reach +-20 but generally should stay in the +-10 range. I am thinking a injector might be putting to much fuel because it reached -25 or the maximum amount of fuel that can be taken away.