Hello everyone,

For the past 2 months or so, I have really gotten terrible gas mileage. I use to average about 200 miles per tank before my gas light comes on. Now, My gas light comes on at about 170 miles.

Nothing about the vehicle has changed (same tires, bumpers, roof rack). I have even eased up on the gas pedal too. The only thing that I can think of was that i got the vehicle serviced for the 100K tune-up and a new alignment. But now I am losing about 30 miles per tank and i can't figure out why.

Has anyone had this problem? Could it be the O2 Sensors that is burning more fuel than needed? Any information would help. Gas Prices are killing me and the extra 30 miles per tank would help. I just don't want to take it to a shop and have them charge me $800 to fix a small problem, which might cost more that the gas that i am losing....

First, you need to be checking your mileage based on how much fuel you are using, not when the idiot light is coming on. The procedure is pretty simple.

Fill the tank.

Drive until you need to refill.

Fill the tank again, taking care to try to fill the tank to the same level.

Divide the miles driven by the gallons of gas.

Right now you have no reliable metric. You may or may not be using more fuel. The light is not an accurate measure.

Second, nearly everyone will get worse mileage in the winter. Not only does it take a bit longer to warm up, but the ethanol content is higher in the winter.

Also, driving conditions may be less condusive to good mileage in the winter, even a California winter.

Above is good advice. If you do go looking for a mechanical fix, here's a list of things to try:

http://www.4x4wire.com/forums/showflat.php?Cat=&Board=UBB86&Number=591821

I tried that too, since the fuel gauge on Isuzus don't work too well. I was actually hoping it was just that, an inaccurate gauge. But its not. When the gas light comes on and I have to refill, Its at approx 17 Gallons (+/-) 0.1 of a gallon. I am using up the same amount of fuel when the light comes on, but losing about 30 miles per tank.

I have driven this rodeo for about 3 years, Winter and Summer, and the mileage has been pretty consistent until the past two months. where it just tanked.

I tried that too, since the fuel gauge on Isuzus don't work too well. I was actually hoping it was just that, an inaccurate gauge. But its not. When the gas light comes on and I have to refill, Its at approx 17 Gallons (+/-) 0.1 of a gallon. I am using up the same amount of fuel when the light comes on, but losing about 30 miles per tank.

I have driven this rodeo for about 3 years, Winter and Summer, and the mileage has been pretty consistent until the past two months. where it just tanked.

Take it back to the shop that did the alignment, have them check it out. Bad alignment can effect mileage and tire wear.

I'd vote for checking the Catalytic (is that how itÆs spelled?) converter.
Mine was plugged about 6 years ago and I could only get about 200 miles per tank. It eventually caught fire. Luckily it was a typical Seattle Autumn day (pouring rain) and I was able to get the fire out quickly and it only burned some of the rubber exhaust hangers. After I got the vehicle home, I took the Cat off and it was melted almost completely solid inside. After I "fixed" it and put it back in, the mileage shot through the roof, and the power increased considerably to boot.

Hmmm.....Its funny that you say that. Because I totally forgot about it. I had one of my catalytic converters replaced about 3 months ago. They replaced that and a front axle that had a worn out CV joint on it. It could have also stemmed from that.

Also make sure you are getting gasoline with no ethanol. Ethanol has been showing up at a lot more stations lately (varying blends) and will definately decrease your mileage.

swap gears. i just installed 4.77;s i'll let you know how they go.