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1994 chevy, bad gas mileage.....


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Guest
Anonymous Poster
mwgrant129@aol.com

Dec 31, 2006, 10:52 PM

Post #1 of 5 (4765 views)
1994 chevy, bad gas mileage..... Sign In

I have a 1994 Chevy K-1500 6 cyl pickup with 178,000 miles on it. The truck still runs great but it gets very bad gas mileage. Put in plugs, wires, cap, rotor, gas filter, air filter, pcv valve. The end of the plug looked white when I took them out. Would this have anything to do with it, maybe needs a carb adjustment? Is there any other gas filters on this truck besides the inline filter along the frame? Any ideas what I could do to get better gas mileage? I think the catalytic converter is the original on this truck. Would that have anything to do with it?


steve01832
Veteran
steve01832 profile image

Jan 1, 2007, 4:46 AM

Post #2 of 5 (4759 views)
Re: 1994 chevy, bad gas mileage..... Sign In

Try replacing the oxygen sensor(s). If it is not switching from rich to lean it will tell the PCM the wrong info. The PCM uses the 02 sensor signal to adjust the air fuel mixture in closed loop (engine at normal operating temp). If the sensor is dead and is staying in lean mode, the computer will pulse the injectors longer and the vehicle will run rich which will use a lot more fuel and could damage the engine and catalytic converter over time if the condition is severe.
The fuel filter on the frame of the truck is the only fuel filter on the vehicle.
Also, the high mileage on this engine is also a fuel consumption factor. It has wear and the original tolerances are now greater. The rings, valves, cylinder walls, etc.. have the usual wear which will increase fuel consumption. You can try using the motor oils designed for high mileage engines. The oil has a molecular structure that bonds better to metal and fills in the gaps. I have seen some vehicles respond better to this oil and it is the same price as any other motor oil.
Start with the oxygen sensor and see if you get better fuel economy first. Good luck and post back to let us know how it works out.

Steve


Guest
Anonymous Poster

Jan 1, 2007, 7:59 AM

Post #3 of 5 (4758 views)
Re: 1994 chevy, bad gas mileage..... Sign In

Thank you, I will start with the oxygen sensor and let you know. Thanks again............


Guest
Anonymous Poster

Jan 1, 2007, 8:38 AM

Post #4 of 5 (4757 views)
Re: 1994 chevy, bad gas mileage..... Sign In

What would go wrong with this sensor? Would I have an engine light go on if it was bad? Does something go wrong inside the sensor or do they just cake up with stuff on the outside of the sensor. Before I go out and buy a new one, can I just take this one out and clean it, or is there anyway to check them before buying one.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jan 1, 2007, 11:42 AM

Post #5 of 5 (4756 views)
Re: 1994 chevy, bad gas mileage..... Sign In

Plugs: If they all look the same that's a good sign.

It doesn't really matter but what six is in this full size truck?? Must be a 4.3 which has been a good engine in my experience. It really is a Chev. 350 with two cylinders cut off.

Carb??: Doesn't this have Central Fuel Injection which kinda looks like a carb?? Either way I don't know of any adjustments except 'puter controls that should trigger a check engine light.

Is the truck really running well? And what is your expected fuel use? I own a '97 with V8 that doesn't get diddle for MPGs because I only use it to plow snow and go to the dump -- so no surprize.Mad

Bonne Ane, Tomas







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