[netguru]

I have 203 miles @1/4 mark on my this tank of 17 gallons i had got 170 miles around the 1/2 way mark what happened? it run fine changed plugs and cam sensor that was malfuctioning. thought on Ethanol as seeing I live in South Dakota Good or Bad?Please Help!

 

[OneFore9]

I copied this from Bob Sikorsky's column a while back:

"Whenever a vehicle experiences a sudden decrease in fuel economy, one of three items is likely to be the culprit.

First, an oxygen sensor gone haywire can cause a sudden and dramatic decrease in fuel economy.

Second, the coolant-temperature sensor may be out of whack. If this sensor malfunctions, the result will be similar to that of a bad O2 sensor, a sharp decrease in fuel economy.

Third, a failing EGR (exhaust gas recirculation) valve causes the engine to burn more gas than is necessary. More gas burned to travel the same distance equals, yes, a decrease in fuel economy.

Other sensors that may play a part in the fuel-economy equation include the throttle-position sensor and the EGR-position sensor. But my money says that it's one of the first three that is causing your sudden decrease in MPGs."

 

[netguru]

MPG & sensors

I have notice anything fan run to cool car no codes from failed sensors other than the aformentioned cam sensor. Car runs fine otherwise.

 

[froggy81500]

If you're talking about E85 when you mentioned ethanol, don't These, and most cars on the road, are not designed to run on 85% ethanol. The gas you may be using could have as much as 10% ethanol, which is used as an oxygenate at that low a level, and will be fine for pretty much everything on the road today.

One thing missing from that list of possibles (all of which BTW would set the CEL on) is tire pressure. Check your tires. Low tire pressure will cost you. Tire pressure is one of the biggest culprits when it comes to increased fuel usage.