Terrible mileage

Tiny
SUJDAK
  • MEMBER
  • 2001 PONTIAC GRAND PRIX
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 122,200 MILES
2001 Pontiac Grand Prix with the 3.8 is getting about 14.5 mpg in town, check engine light is on. Registered a code saying the fuel/air mixture was too rich, 1 culprit for just one bank registering an error as opposed to both was a defective oxygen sensor. Should that just be replaced or are there other issues that couple come into play like a vacuum leak? Would old plugs and wires exacerbate the problem?
Saturday, March 26th, 2011 AT 5:46 AM

1 Reply

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Probable causes of an engine running rich are as follows:

Excessive fuel pressure can be cause by restricted fuel return line
2. Defective Oxygen Sensors.
3. Leaking injectors and fuel pressure regulator.
4. Coolant temperature sensor out of calibration.
5. Restricted air intake system.
Was this
answer
helpful?
Yes
No
Saturday, March 26th, 2011 AT 6:18 AM

Please login or register to post a reply.

Related Check Engine Light Content

Is it Safe to Drive Check Engine Light?
VIDEO
Is it Safe to Drive Check Engine Light?
Instructional repair video
Check Engine Light
GUIDE
Check Engine Light
Why is my check engine or service engine soon turned on? In this guide we talk about what this is associated with this notorious light, what it is used for and what you...
VIEW MORE