My car's MPG is sooooooo weird.
 

In the start of the week I was getting 12MPG...I filled up 5 gallons right as the light came on and it took 60 miles of driving for the light to reappear. :wtf: Two days ago, I filled up full and now my needle is exactly at the halfway mark @ 200 miles driven.

I'll be getting a complete tune up in about two weeks done (car has 58.5k miles now, so it's almost that time). I'll be replacing sparks, air filter, oil, and I'll do the seafoam. What else should I do? And what could be contributing to such a sporadic MPG?

Edit: I think I may need a new CAT too. :\

it could just be the gas you got...once i got a tank of gas and i only got 170 miles off a full tank (with conservative driving). I filled up the next tank with Shell gas and i got my normal gas mileage (21-22) mpg, mixed driving.

daym wierd ****

i think the tune up will help. last week i got only 150 miles driven when it got to the half way point and this week after i got an oil change i got 200'ish when it got to the half way point. i'll have to wait for my next fill up to count the mpg to see if it got better or something. before oil change i got around 18mpg.

The miles difference you are seeing maybe a result of the summer gas being used now. They use different gas in the winter. It does effect MPG. My fater drives 85miles oneway to work everyday. He losses about 4-5mpg in the winter with the different gas. Just thought I'd throw that in to keep anyone from thinking there car is messed up and it not be.

Never go by what the gas tank reads. Just read how much gallons you put in each time and you should get a more accurate reading. It takes my car twice as many miles to get from full to half than it does from half to the light.

ya that's true...my needle was half way yesterday and today after driving to work (17 miles) the needle went down pretty quickly like almost to the next line haha

During winter...
 

You guys know that the MPG will always go down during winter, that is because the air is at the differnt pressures when it's colder. When that happens, the gas in the tank compreses and the car can't get the normal milege like in the summer. My MPG always go down in the winter and then goes back up during summer.

But anyways I think I still need a tune up. Where's a good place that I can go to to get the seafoam and stuff like that??? Jiffy Lube maybe?

Yeah, but this isn't a case of winter vs summer gas. This was done all within the same week using the same gas station with the same driving patterns and habits. =\

what i noticed is different gas sations have different tyopes of gas..some good some bad.....go witha reputable gas ssation and you shoud see MPG back to normal. Has happened to me a couple of times in Toronto....Now i just stick with one station....SUNOCO...94 Octane BAYBEEE!!!!

MPG is hard to determine correctly with partial fill ups. Sometimes I fill up at 14.7 gallons when the light goes on, other times at 16.1 gallons. The gas light indicator and mileage in between partial fill ups are inaccurate

Aight in NYC, every gas station uses different gas brands.
In the rules of the gasoline franchise, a gas station needs to buy a minimum of gasoline from their source. The rest, they can purchase from wholesale in order to compete with gasoline prices. Being that NYC gas stations have so many consumers, they can sell the minimum very quickly and then can get the cheap gas.

I only get gas from 3 gas stations near me in which I know that the gasoline is always the brand specified. Its the 2 mobile stations in brooklyn on Knapp Street, they owned by the same owner and I get the best gas milleage. I usally get 230-250 city driving, but note that I have a heavy foot and my SES light is on. I usally get 170-200 to the 15 gallons.

Gene