p0171 failed smog, fuel too lean

1999 TOYOTA COROLLA
200,000 MILES • 1.8L • 4 CYL • AUTOMATIC
Avatar
MACYB66
  • MEMBER
  • 2 POSTS
my car failed smog there was a code P 0171 that came up I have changed the spark plugs the wires the valve cover gasket and o2 sensor but the check engine light still remains on started the diagnosis on it everything turned out fine but still have p 0171 any advice
Feb 9, 2015 at 8:59 PM
Advertisement
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
p0171 means the engine is running lean, check fuel pressure with a gauge and for a vacuum leak.
Feb 10, 2015 at 5:48 AM
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,870 POSTS
The first thing I would do is change the fuel filter which will restrict the amount of fuel the engine is getting causing the lean code, here is a guide that can help you understand the lean code as well.

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

Here is the location of the fuel filter so you can swap it out. Check out the images (below). Please let us know what happens.


Image (Click to enlarge)
Attached Media
Jul 6, 2024 at 1:09 PM
Advertisement