Hi all,

I recently got a custom tuned by a reputable shop. I made 350awhp/380ft-lb. The mods I have is an AMS FMIC, AMS LICP, walbro 255 fuel pump, HKS RS Intake, Hallman MBC, Cossworth cams and ARP Headstuds.

Everything is great except for one issue. The issue Im having is that every time I drive locally, NYC blocks and stop and go traffic, my check engine light would come on. The code I keep getting is P0171, System too lean. Once the SES lights comes on or even before the SES light is about to come on, my idle becomes very eradict. It drops pretty low to a point where it's about the stall. This issue only happens on low rpm, when I drive slow, or when Im stuck in traffic.

The tuner and I narrowed it down to the injectors is either bad or the stock ECU cant properly regulate the 680cc injectors. The tuner made a few tweaks on the fuel mapping today and I still get the same issue.

What do you guys think is the problem? Im thinking I should remove my HKS RS Intake and put my stock airbox back in... Maybe I could lessen the air coming into the intake when I let go of the throttle. Do you guys think that would help remove the CEL?

I'd like to get this resolve as quickly as I can so If anybody has any comment or any idea what could be the problem that would great help.

Thanks for looking.

 

make sure he did the injector scaling right...ie the stock 560s are input in the injector scaling value as 513. That is if you are using ecuflash.

 

Thanks for the response,

The tuner said the issue is not the scaling. Ruling out the scaling what else could it be, bad front o2 sensor? I only have 8600 miles on the car though.

 

when i had my cams installed i got the system to rich CEL, my tuner just did more tuning on the car, scaled the injectors more and it went away