2001 Lexus IS 300

Engine Performance problem
2001 Lexus IS 300 6 cyl Two Wheel Drive Automatic 120000 miles

my check engine light keeps coming on. It gives me code p0174 and p0171 indicating that bank 1 and bank 2 is running too lean. Does this mean there's a vacuum leak, if so where should I start looking for the problem?
November 5, 2008.

Hi philip_ino,

Thank you for the donation.

Yes, it could be a vacumn leakage and you need to check all the hoses at the manifolds. Is the idling rpm stable?

The other possible cause is the fuel filter, if it is clogged, the fuel supplied would be lean.

Nov 5, 2008.