Gas mileage decreasing?
07-07-2008, 10:27 AM
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Gas mileage decreasing? Ok over the past few tanks i've noticed my mpg getting worse and worse. My driving habits haven't changed. I drive about 50% hwy and 50% cty and on my last tank I got 15.22 mpg. Thats terrible. I have new plugs/wires, new fuel filter, and a good dyno tune. Im not throwing any codes either. The o2s were extended by myself and are the originals as far as I know, so they have about 88k miles on them. I only use 93 octane at exxon, and I tried a gumout fuel system cleaner that obviously didn't work. I don't really want to buy new o2 sensors either because of some cash flow issues at the moment lol. What should I do?
07-07-2008, 08:20 PM
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It might have to do with the amount of ethanol being added to gas now. I have heard about people getting less mpg and even throwing some codes just because of the gas.
07-07-2008, 10:17 PM
#7
this is for everyone, go to a shop and get them to do an injector flush, like a real one, not one of them ***** pour a bottle in the tank and drive off. i'm talking about hooking it up to your fuel rail, disabling your fuel pump and running if off of their container....making **** loads of smoke cleaning it out (no seafoam wont take care of what i'm talking about, i'm talking about actually cleaning the injector's themselves) that ALWAYS helps increase mileage, i've had people gain 5 mpg just because their car's had 150k miles on them and they never knew you were suppost to clean them up professionally.
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07-07-2008, 10:46 PM
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Well, you can do it your self. Get a pressure can, dissable the fuel pump and let it rip.
The only propblem is finding the stuff. They use to sell that **** back at school(UTI).
Or you can just hand over 80 Bucks and have a shop do it. It really does make a difference.
The only propblem is finding the stuff. They use to sell that **** back at school(UTI).
Or you can just hand over 80 Bucks and have a shop do it. It really does make a difference.
07-07-2008, 10:48 PM
#9
just cheaper and faster to let a shop do it, just do a 50/50 mix of the cleaning and gas, and presurize the canister to 65 psi and start playing with the pedal making sure not to back fire it lol, bet someone can burn their leg hairs by walking past the exhaust tail pipe 
lol
lol 
07-08-2008, 07:24 AM
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Yeah the filter is pretty clean. Its a volant intake so I clean it and re-oil it about once every 5000 miles. Plus I did the FRA mod so the filter gets dirtier quicker. As far as rpms go, it hardly ever sees above 2000. I skip gears most of the time as well.
I have thought about this but I haven't heard of anyone else getting worse mileage. My dad fills up at the same station and actually got the best mileage he's ever gotten a couple taks back.
I might have to try this. Where can I get this pressure can at?
Yeah I know I probably should but thats kind of a last resort just because those corvette o2s are like 70 bucks a pop.
I may try filling up at a different station next time just to try and eliminate any variables. And thanks for ther replies!
just cheaper and faster to let a shop do it, just do a 50/50 mix of the cleaning and gas, and presurize the canister to 65 psi and start playing with the pedal making sure not to back fire it lol, bet someone can burn their leg hairs by walking past the exhaust tail pipe lol
lolI may try filling up at a different station next time just to try and eliminate any variables. And thanks for ther replies!
07-08-2008, 08:16 AM
#14
the container that im talking about is about 400 bucks.... lol see why i said its easier to get the shop to do it. there are pressurized cans that have the stuff already but you have to buy a box at a time and really is more of a hassle since you have to use their brand only
07-08-2008, 10:05 AM
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the container that im talking about is about 400 bucks.... lol see why i said its easier to get the shop to do it. there are pressurized cans that have the stuff already but you have to buy a box at a time and really is more of a hassle since you have to use their brand only
07-08-2008, 11:19 AM
#16
Stop using Exxon gas. They don't put enough detergent in it to keep the engine clean. http://toptiergas.com/ GM recommends going to one of these retailers: http://toptiergas.com/retailers.html A few tanks of good gas may help.
You can find one of the treatments folks are talking about above referred to commercially as a MotorVac CarbonClean treatment. I paid a local shop $85 to do the treatment for me and got an additional 2 mpg in the city and on the highway. With the current price of gas, it will pay for itself after around 15 fill-ups.
You can find one of the treatments folks are talking about above referred to commercially as a MotorVac CarbonClean treatment. I paid a local shop $85 to do the treatment for me and got an additional 2 mpg in the city and on the highway. With the current price of gas, it will pay for itself after around 15 fill-ups.
07-08-2008, 01:41 PM
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Stop using Exxon gas. They don't put enough detergent in it to keep the engine clean. http://toptiergas.com/ GM recommends going to one of these retailers: http://toptiergas.com/retailers.html A few tanks of good gas may help.
You can find one of the treatments folks are talking about above referred to commercially as a MotorVac CarbonClean treatment. I paid a local shop $85 to do the treatment for me and got an additional 2 mpg in the city and on the highway. With the current price of gas, it will pay for itself after around 15 fill-ups.
You can find one of the treatments folks are talking about above referred to commercially as a MotorVac CarbonClean treatment. I paid a local shop $85 to do the treatment for me and got an additional 2 mpg in the city and on the highway. With the current price of gas, it will pay for itself after around 15 fill-ups.
07-08-2008, 07:55 PM
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also put into consideration that theres other things that affect gas mileage as well, such as wieght, tire pressure, aerodynamics--i'm gonna go out on a limb an assume you haven't been adding wieght to the vehicle so have you checked you're tire pressure?