Eating gas like crazy

[swinsoneric]

I have a 1998 malibu and it is eating gas like crazy. I changed the plugs, fuel filter and air filter, plus i only use 93 gas. Everyday i put damn near $20 in the tank, and i don't even drive the car alot. Can someone please help me.

[RJ MALIBU]

I HAVE AN 03 MALI AND I ALSO NOTICED IT GETS HORRIBLE GAS MILEAGE ABOUT 140/160 MILES PER TANKFUL N E 1 HAVE ANY ADVICE? I DO HAVE A CAI

[swinsoneric]

I thought that a CAI was suppose to help with better gas mileage .

[igkyoa]

a CAI will increase mileage by a very small amount, it sounds like you two have gas leaking or something, or possibly your oxygen sensor needs to be replaced i dont really know but thats not right there is something you can fix i bet

[BeatnikTermite]

I believe you have a leak somewhere. In even the worst dirty city driving, the Malibu should not be getting less than 15 MPG, which equates to about 200 miles per tank.

Additionally, A CAI will reduce your MPG.

Gasoline atomizes poorly when cold. Fuel must be atomized prior to being injected into the cylinder. If a smaller percentage of the fuel atomizes, more fuel must be added to provide enough to burn. This is why a CAI will provide better Torque and HP. More gas = more power. All cars run rich when they are cold, the colder the engine/air, the richer the mixture. After the engine is fully warmed up, cold ambient air will still continue to cool as it mixes with the fuel, causing poor atomization, and therefore poor gas mileage. In addition a CAI is usually coupled with a high flow cone type filter, which will allow more particles into the mix, and contribute to a dirtier mixture. This will lead to additional sediment in the block, on the valves and in the Cat. Converter.

Besides, if a CAI increased HP AND increased Torque AND increased MPG, why would they not be standard on all models?

[swinsoneric]

How would i know if the oxygen sensor is bad and if i have a gas leak, when the car is sitting still i don't smell any gas.

[igkyoa]

if you have a gas leak it should be pretty obvious like gas on the ground, and your oxygen sensor can be checked at most auto parts places or the dealer (but dont go to the dealer)

[swinsoneric]

I know i don't have a gas leak. If the oxygen sensor was bad would the check engine light come on.

[porrsher]

Good rule of thumb is to replace the 02 sensor every 50k miles, in addition to that I would also do a simple tune up including air filter, plugs, fuel filter etc. The engine light should come on if one of the sensors fails which sounds like none of yours have. Another thing to remember is your driving habits, Be easy on the skinny pedal and gas mileage will also increase.

[astrosurfer]

there is a possibility that your catalytic converter is getting stopped up
have you noticed any difference in performance?
sluggish take off, or intermittent decelleration,however slight?
happened personally to me, got about 140 miles to a tank, which sucked at todays gas prices, and only showed an engine light towards the end when i was getting tired of the poor performance/mileage

[swinsoneric]

How can i check to see if the catalytic converter is getting stopped ? By the way i have 143878 miles. But i can honestly say that i haven't had that many ploblems with my car.... (Knock on wood)

[johnschmitt]

This will sound weird, but you can try driving it around for a while at night, stopping, and peeking under the car to see if it's glowing. They get really hot when they're stopped up.

[swinsoneric]

I'm going to try that, but what if it is stopped up is it pricey to get it fixed or even removed. What would happen if i get it removed ?

[BeatnikTermite]

Originally Posted by swinsoneric

I'm going to try that, but what if it is stopped up... What would happen if i get it removed ?

You would pollute my air, even more than your extra gas burning does, so don't even think about it.

If it needs to be repaired, repair it. A complete Cat-back exhaust job will run you about $200 depending on options (Stainless, welded, etc.). just the Converter should be about $50.

[Arctic388]

i try to buy my gas at the same station for quality reasons and its feasible for me. so i kept getting from a Shell branded station then one day got it at the next station Phillips 66 ( which i am boycotting Phillips/Conoco now for not supporting the 2nd ammendment ) but anyway i increased my distance on that tank with the same driving as i always do by 55 miles before i filled up again. i always run till the light dings then fill up. really shocked me but i've repeated my experience twice so far so i know it wasnt some fluke thing.
so try a different station that might help.

also check your fuel pressure regulator if it looks like it has accumulated leaky oil or dirt then it is probably leaking. mine did on a 4 cylinder.