Onetogofast

iTrader: (9)

My buddy has a 2009 Denali Sierra, had it scanned for the light being on, reads rich bank one and two. Air filter does not look bad and when cold started it pops up to 1000rpm falls to 200 and then hops up to 1500 a sits for a while. From what I understand this truck has a fuel pressure module instead of a pressure regulator? Are these know for being trouble makers? What other option could it be? Thanks Guys

03sierraslt

iTrader: (22)

Dirty MAF Sensor, although when cold it should be in open loop for fueling thus the MAF is not used. Hmmmm

Onetogofast

iTrader: (9)

He ordered a cold air that will be here tomorrow so when I put it on I will descreen and clean the MAF and see if that helps