Contour Enthusiasts Group Archives Forums General Troubleshooting Really bad gas mileage lately...

Very odd. Since I started work near Fort Lauderdale, I commute about 20 miles each way from home to work. But recently, it's been taking more and more fuel to make my destination.

My school is about 35 miles away from my place, and both ways, it takes about 3/5 of a tank to make the round trip. Before, it was a little under a quarter tank.

Any speculation as to what may be causing it? I do have an oil change coming up within a month.

O2's might on their way out. It may not be that. could be a number of things.

get some basic maintenance done and go from there, make sure the filters are new, plugs are good and gaped right, plug wires and in working order, run some fuel injector cleaner and scan for pending code and see if it leads to anything

but I agree the O2 sensor or cat monitoring sensor might be on the way out

...and clean your MAF sensor while you're at it.

Post-cat O2 sensors will not effect fuel economy in any way.

Steve

I had the a similar issue with my 98. The damn thing would eat gas and it had an awkward idle (would be start way high, drop to ~500-600 rpm). I tried alot of things. And It ended up 6 months later (I only drive about 4K a year) The O2 sensor completely crapped on my way back from school.

So your case may be a dieing 02


But lets not forget other reasons why:

-Dirty MAF Sensor
-EGR Clogged
-EGR system disfuctional (Broken/bad vaccuum line)
-DPFE sensor failing
-plugs? Last time you changed them?
-Air filter, not dirty or from ebay...
-small air leaks make lean codes, but will fudge with rest of computer controlled systems
-Summer time now, are you using A/C?
-Are you hauling around any extra weight? (My father forgot he had 2 x 32 count pack of bottled water in the trunk for a little over 2 weeks)

Thats probably best place to start. Good luck

Check for dragging brakes, low tire pressure. A/C only takes about 2 mpg..