[KOB-CHRIS]

Hi everyone, so I have a 08 Tundra DC 5.7L and I got the dreaded P0171 and P0174 code. Researched a little and found that mine is most likely a vacuum leak because my % goes down as the load goes up (throttle) and if it were fuel related the % would go up as the load went up.I have a scanner the can do Live update and I am getting 14.8% at idle, 7.0 % at 65 MPH, on Bank 1 and 17.2% at idle, 8.4 % at 65 MPH on Bank 2.

Question 1: Since Bank 2 is higher could one assume that the leak is around that side of the engine?

Question /Comment 2: If you have a scanner with a live update feature, what are your reading? (STFT, LTFT, ALC%, etc)

Thanks in advance

 

[Ronnie Player]

I know this post is a few months old but there is an excellent 2 part video on this subject. Go to www.youtube.com and type in " Secret of Engine Diagnosis- Fuel Trims Pt. 1, He is a scientist trying to find a cure for cancer and his hobby is engine repair. His logo is Shrodingers Box. This man knows his stuff.....