bad gas mileage

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bad gas mileage

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Chevrolet >> Chevy Trucks, Vans & SUV's >> Silverado >> bad gas mileage

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bad gas mileage - 2/14/2007 8:06:22 PM

wert

Posts: 2
Joined: 2/14/2007
Status: offline

I have a 1990 chevy 4x4 reg cab im have problems with my gas mileage just started happing about a month ago when it got really cold somebody told me to change the o2 sensor and then somebody tole me to change the coolant temperature sensor i dont know what to do going crazy, people are telling me differnent things any help .

Post #: 1

RE: bad gas mileage - 2/14/2007 11:27:25 PM

Waboom!!

Posts: 79
Joined: 1/13/2007
Status: offline

from your description I would say the thermostat /coolant temp sensor. And definately not the O2 sensor. the cold won't affect that unless it's a coincidence.

(in reply to wert)

Post #: 2

RE: bad gas mileage - 2/17/2007 12:42:06 AM

kcb37

Posts: 504
Joined: 7/3/2006
Status: offline

How long has it been since your last tune up? Dose your engine light come on? I am going to assume you don't have any other problems since you didn't say anything but your gas mileage. You also said it's cold. When you start a gas engine in cold weather you have to run a rich mixture to get enough of the gas to vaporize to make it burn. That is done on old cars by a manual choke, then an automatic. If you have a factory carb you should have an atuomatic choke. Throttle bodies and fuel injection don't have a choke, but the computer does control that. When a car is warm and running correctly it will run around a 14 to 1 air to fuel, when it is cold it will go to around a 9 to 1 to get started and warmed up. So if it is cold and your choke is on and you don't let it warm up and only drive a short distance your engine will not warm up completely, and your choke will not shut off compeletly, thus you use more gas to keep it running.

(in reply to Waboom!!)

Post #: 3