The service engine soon light lit on my 2001 f-150 w/5.4 V8. I checked the code and it came up as a P0171 and P0174 (System Lean Bank 1 and 2 respectively). It also appears the when it warms up the RPMs tend to fluctuate. thought it might be because the injectors need to be cleaned so I put a fuel additive in to get rid of any build up in the injectors and it appeared to improve the problem. The RPMs still fluctuate but not as bad. The truck does have a K&N Filter and Intake on it and have heard that sometimes it could cause the mass air flow sensor to get dirty and that this could be a cause of the problem. Is this possible, and could it be as simple as cleaning the Mass Air Flow Sensor?
Dec 29, 2007 at 12:59 AM
