Terrible Gas Mileage

[absc400]

I'm getting terrible gas mileage on my 92 sc 400. Only 10 miles per gallon, and at $4.12 /gallon I need some advice. Recently had the one front O2 sensor replaced could that have anything to do with it. :(

[sc4sooner]

I dont know what could be wrong but 10mpg is terrible, i as well have a 92 sc400 and even with a heavy food i still get 16 or 17 in the city and 22 to 23 in the highway.

[Lethal_Threat]

I'm getting terrible gas mileage on my 92 sc 400. Only 10 miles per gallon, and at $4.12 /gallon I need some advice. Recently had the one front O2 sensor replaced could that have anything to do with it. :(

A MASSIVE help for me was to change the fuel filter, i gained 7 mpg right off the back, upgrade to a fram. You'd be suprised at how much less gas the engine burns if it flows better. Seems kind of backwards, but it works. Also pick up a throttle chamber cleaning kit from BG products, about 25 bucks, that works awesome too, there is alot of build up in those throttle bodies, esp around the butterfly valve.

[SCdriver]

Your SC400 should get 14-16 mpg in the city and 21-25 mpg on the highway depending on your driving style. Your car should be tuned if it hasn't been for some time. Simple matters like changing your air filter (OEM paper or K&N), fuel filter,spark plugs (iridium NGK or denso), oil and oil filter ( mobil one/amsoil etc and lexus filter) as well as inflating your tires properly should get you back to OEM mpg specs. I also agree with the prior suggestion of putting a good additive in your fuel to clean your intake/valve system. You can wait until you are down to 1/4 tank and then put in the large 20+oz (or two small 12 oz) bottle(s) of chevron techron complete fuel system cleaner and run it to near empty and if that doesn't work you can see posts on using sea foam cleaner. A catalytic converter cleaner might also be used after the other cleaners but I'm not sure if it will increase mpg but if you have a sulphur exhaust smell, it might help.

[eds92sc]

I'm getting terrible gas mileage on my 92 sc 400. Only 10 miles per gallon, and at $4.12 /gallon I need some advice. Recently had the one front O2 sensor replaced could that have anything to do with it. :(

A MASSIVE help for me was to change the fuel filter, i gained 7 mpg right off the back, upgrade to a fram. You'd be suprised at how much less gas the engine burns if it flows better. Seems kind of backwards, but it works. Also pick up a throttle chamber cleaning kit from BG products, about 25 bucks, that works awesome too, there is alot of build up in those throttle bodies, esp around the butterfly valve.

REALLY? I am getting my fuel filter replaced as we speak. I hope to improve my mileage like yours. I usually get combined 18-19 mpg. Everything is stock in my car.

[renman]

I'm getting terrible gas mileage on my 92 sc 400. Only 10 miles per gallon, and at $4.12 /gallon I need some advice. Recently had the one front O2 sensor replaced could that have anything to do with it. :(

A BFI will help with gas mileage and performance.

[Lethal_Threat]

I'm getting terrible gas mileage on my 92 sc 400. Only 10 miles per gallon, and at $4.12 /gallon I need some advice. Recently had the one front O2 sensor replaced could that have anything to do with it. :(

A MASSIVE help for me was to change the fuel filter, i gained 7 mpg right off the back, upgrade to a fram. You'd be suprised at how much less gas the engine burns if it flows better. Seems kind of backwards, but it works. Also pick up a throttle chamber cleaning kit from BG products, about 25 bucks, that works awesome too, there is alot of build up in those throttle bodies, esp around the butterfly valve.

REALLY? I am getting my fuel filter replaced as we speak. I hope to improve my mileage like yours. I usually get combined 18-19 mpg. Everything is stock in my car.

Really, my filter was plugged horribly, and the engine had to strain so much harder to do work that it killed my mpg's. So did it help? Did you try some additives in your fuel and a throttlebody clean up as well?

[eds92sc]

I'm getting terrible gas mileage on my 92 sc 400. Only 10 miles per gallon, and at $4.12 /gallon I need some advice. Recently had the one front O2 sensor replaced could that have anything to do with it. :(

A MASSIVE help for me was to change the fuel filter, i gained 7 mpg right off the back, upgrade to a fram. You'd be suprised at how much less gas the engine burns if it flows better. Seems kind of backwards, but it works. Also pick up a throttle chamber cleaning kit from BG products, about 25 bucks, that works awesome too, there is alot of build up in those throttle bodies, esp around the butterfly valve.

REALLY? I am getting my fuel filter replaced as we speak. I hope to improve my mileage like yours. I usually get combined 18-19 mpg. Everything is stock in my car.

Really, my filter was plugged horribly, and the engine had to strain so much harder to do work that it killed my mpg's. So did it help? Did you try some additives in your fuel and a throttlebody clean up as well?

Not really. After the fuel filter was changed, I am still getting the same 18-19mpg combined. I used Seafoam with a full tank of gas. It seemed to make the engine run a little smoother. I didn't use anything for the throttle body. Did you take off the throttle body intake to clean up the throttle body?