I have a 2005 r53 with a 17% pulley reduction. I received a few codes p0171, p0131, and p0455. I replaced the gas cap with oem, and o2 sensor with exact fit NTK sensor. Still receiving codes, could larger injectors be needed or possibly something else?
Thankyou for your time.

 

When you say that you have a 17% pulley, did you just replace the pulley and have gotten the codes? I've not looked up the codes, but I don't believe larger injectors will solve your problem. Did you put cooler plugs in?

 

Hi and welcome to NAM!
Congrats on your R53 buy!
Pics?

 

The previous owner put the pulley reduction in. Yes, the previous owner put 1 step colder plugs in.

 

Get inpa an reset your fuel adaptations.

 

any suggested INPA?

 

Use this.

 

Just having a pulley won't cause codes. You need to just diagnose the car as if it didn't have a pulley and was stock.