maybe running rich? (1 Viewer)

[livelarg]

My truck has been getting horrible gas mileage. no big suprise there.
I have noticeing a gassy smell around my truck. I thought it may be a gas leak, but nothing found. I replaced the fuel sock in my tank when I was checking for the leak.
anyway, I was thinking it may be that my truck is running rich. When I bought it 5 months ago, I gave it a tune up, replacing everything except my O2 sensor. could a faulty O2 sensor be making it run rich?
and if I were to replace the sensor, should I/ can I reset the computer?
If not the O2 sensor, is there anything else that might cause the truck to run rich?

Thanks
Kent

 

[livelarg]

would timing make it run too rich?

 

[TiredIronGRB]

Probably the fuel pressure regulator.

 

[sdbrassfield]

Wow, poor fuel mpg could be caused by something as simple as timing, clogged air filter, tires (underinflated, and/or are your 32" tire are not calibrated w/ speedo/which was calibrated to original tires - have seen this make a 2 mpg difference when calculating mpg), or even a fuel leak if you are smelling the fuel. The smell could be from your charcoal cannister/eec system. Check cannister and all hoses for damage.

A little more complicated could be a bad EGR or clogged PCV Valve which can affect economy. Clogged exhaust maybe? And yes a bad O2 sensor can affect your economy since it is not sending correct voltage info to vacuum advance and other emmision controls. Have you set any codes in the ECM?