Running lean. Cant figure out why!!!!

[b5a4gt28]

So i had bought a wideband and recently after stepping on the gas i saw it was reading 13 then 14 and then 15 by redline. I checked for boost leaks, I cleaned the maf with maf cleaner, brand new fuel filter, and an adjustable fuel pressure regulator. If I turn the fuel pressure up it still runs the same exact thing. As soon as i step on the gas it will start at 12 and then just climb from there. At idle and under a little bit of load it run 14.5 - 15. Before the car use to hold around 12. Now it leans out more as the rpms climb. I have a gt28rs turbo with rc440's and the pes giac software. I checked all my vac lines and found nothing. I have vag com but i don't really no how to test the maf. I think its either the maf or the fuel pump is running out of breathe. I am not sure that the pump has been upgraded because i bought the car with the turbo setup already on. I am running around 18-19 psi. Let me know what you think.

[kovalevandrew]

My suggestion. Check the injectors are working properly. Haven't heard good things about the RC440's here in SA.

[b5a4gt28]

yea I'm not proud of having them but they always have worked fine so i haven't thought of changing them out.

[kovalevandrew]

Perhaps try and get hold of some others and test with them. At least to rule out the injectors as being the problem.

Some people here run great with them, others have endless hassle, seems to be that they have a lot more "bad" batches than they should. From what i've heard is they work 100% in N/A cars, turbo ones not so well.

[b5a4gt28]

The car ran fine though. how could they of stopped working all of the sudden? The car runs and drives fine until under boost. The only thing i could be thinking of is if they aren't going past a certain point(as in as far as spraying the fuel goes?)