Bad gas mileage after fuel filter change?

[Bear_Slayer]

I just changed my fuel filter and now I'm getting horrible gas mileage... any ideas?

 

[graff104]

Check for leaks?

 

[TomB1269]

Are you sure you installed it correctly. I know the new ones only fit oneway.

 

[Bear_Slayer]

I checked it while I had it running at the gas station, it wasnt dripping or leaking and I felt around to see if it was running down the frame rail to a location that I couldnt see. Didn't find anything. It is installed the correct way, and seems to be fitting properly.

Is it possible that there is a breaking in period?

 

[Rearanger]

....and now I'm getting horrible gas mileage...

How horrible? And how are you measuring, miles per tank or miles per gallon?

 

[Bear_Slayer]

By watching the needle slowly move. I shouldn't be able to watch it move now, when I never did before. Performance has improved though, the truck was slightly sluggish when I started out though.

I never have the money to properly check it (filling the tank) so I mostly just halfass it by putting in an amount and waiting for it to get to a certain point. Yes, I know that isn't the proper way. I will check back later.

 

[Toms01PSD]

Then how are you certain you are getting worse mileage if you fill it to different levels each time you put gas in? If you put 10 gallons in one time and 4 gallons the next time of course you are going to get "worse mileage". The reason being is you are getting less mileage out of the 4 gallons than 10. My truck "tells me" it get's good mileage from full tank to 3/4 and then the needle moves faster between 3/4 and empty. I'm sure others see the same thing with their gas gauges.

 

[Bear_Slayer]

Then how are you certain you are getting worse mileage if you fill it to different levels each time you put gas in? If you put 10 gallons in one time and 4 gallons the next time of course you are going to get "worse mileage". The reason being is you are getting less mileage out of the 4 gallons than 10. My truck "tells me" it get's good mileage from full tank to 3/4 and then the needle moves faster between 3/4 and empty. I'm sure others see the same thing with their gas gauges.

I know I'm getting worse mileage because the needle went from half a tank to a quarter tank driving 30 miles..

Like I said, this happened today. It's not worse gas mileage, it's horrible gas mileage. As in it would have been cheaper for me to drive my fullsize dodge today.

My trucks been acting wierd today. I had a leak in my radiator that prettymuch drained it as it sat infront of my house, but when I put water back in and drove it around.. no leak.

 

[Toms01PSD]

Like I said. The needle likes to go down quickly. Mine does it too.

 

[wahlstrom1]

Only good way of measuring fuel consumption is running several tanks full-emty, as a regular set of guages are fairly broad and even a gallon/litre or two can make a huge difference in mileage calculations.

 

[Bear_Slayer]

Even if my needle was off by a gallon, a 20 gallon tank is roughly 5 gallons for every 1/4 tank. I shouldn't have went through 5 gallons for a 30 mile trip. Even if it was 3 gallons off, I shouldn't go through 2 gallons on a 30 mile trip.

 

[fastpakr]

Stop. Get an accurate measurement and then you can troubleshoot. You're leading yourself around in circles by using bogus information.

 

[RogueRanger316]

do what I had to do....reset the computer, depending on what year model truck you have...I repleced mine back in March and forgot to reset the computer (did it last week due to the same problem) and my mileage/fuel consumption went back to normal. Reason for that, the computer is sending too much fuel to the engine due to the old information stored in the computer from before the fuel filter change. Hope that makes sense.

 

[Rearanger]

Reason for that, the computer is sending too much fuel to the engine due to the old information stored in the computer from before the fuel filter change. Hope that makes sense.

No it doesn't.

 

[turtle3.0]

Even if my needle was off by a gallon, a 20 gallon tank is roughly 5 gallons for every 1/4 tank. I shouldn't have went through 5 gallons for a 30 mile trip. Even if it was 3 gallons off, I shouldn't go through 2 gallons on a 30 mile trip.

I think your biggest mistake is going by the gas gauge. It is just a gauge of approximately how much fuel you have left. Mine takes forever to go from Full to 3/4, then from 3/4 to 1/4 it moves relatively quick. Then 1/4 to E is slow again. That can depend on the type of sender, shape of the tank, etc. etc. etc. You should fill up completely once then drive for a day or two, refill and calculate your MPG. Do this three or four times. The needle on your gas gauge is by no means a precise measurement tool. More than likely you will find that you are getting average fuel economy (15-20mpg) depending on driving habits.