Getting less Milage

[ovcrash]

I use to get around 250Km on a half tank with 91 Octane gas. Now i get around 130 - 150Km on a half tank, what could be the problem ? Need to change air filter? Spark Plug?

Oil has just been change, car does not make any noise, idle looks ok, around 800rpm.

The car is bone stock, it's a 1997 Prelude.

 

[seanjuan]

how are you gauging a half a tank of gas?

IMO the only way to really determine your fuel economy is to fill up at a specific pump, go a few hundred miles (or a few hundred K) and then go back to the same pump and top the tank off again and then dived miles traveled by fuel used

I don't trust my gas gauge, I only trust my trip odometer because stock gas gauges are very inacurate, at least in most of the cars I've driven

 

[ovcrash]

Well before when my gas gauge got to the middle my millage was around 250Km, now for 2weeks now..when my gas gauge get's to the middle my millage is around 130Km so that's how i determine that i don't do as much millage that i use to do...

But why? i always go to the same gas station always take 91 Octane gas...what could affect that? Spark Plug need to be changed? Air Filter? Gas Filter?

 

[seanjuan]

I don't know what would be affecting your mileage I'm just trying to eliminate factors like your gas gauge not working right

as of late my gas gauge has been messed up and it will say i only have 3/4 of a tank right after I filled it up

instead of just going by the gauge, use your trip odometer and divide how far you have gone by how many gallons you put in it is far more accurate and you will be able to see if you are getting the expected fuel economy for your car

 

[starboy869]

did you check your air filter?

 

[saturn_boy96]

seanjuan Posted on Aug 29 2003, 11:05 AM
instead of just going by the gauge, use your trip odometer and divide how far you have gone by how many gallons you put in it is far more accurate and you will be able to see if you are getting the expected fuel economy for your car