Dirty fuel filter, and poor mileage

[JoshBarber]

Could someone please explain to me how a dirty fuel filter can hurt your gas mileage? I currently own a 98 Blazer LT 4x4, and blow through gas way faster then I should. Not sure how accurate the digital reader is, but it says I'm getting as low as 11 miles a gallon (non-highway). Whatever it is, I know it's not right. I did the two simplest things tonight. New air filter, fuel filter, and pcv valve. Only thing that really looked nasty, was the fuel filter. Havent had a chance to see if it made a difference, but time will tell. Any other ideas? And can someone explain how a dirty fuel filter could kill gas mileage?
thanks
Josh
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[BlazerLT]

Engine will go through fuel faster when it is cold out.

Have you tuned up your truck lately? Plugs, wires, cap and rotor?

A plugged filter will cause a lean condition which will have the engine retard the timing to compensate for the lack of fuel flow.

Best to reset your computer so the engine can relearn the new fuel curve now everything is up to snuff.

Also, don't use the digital guage to measure fuel economy, do it the standard way.

Miles/gallons of fuel used

[JoshBarber]

I just bought the truck, so I havent done any of the tune up stuff yet. Do you reccommend I do the plugs and wires if the engine seems to be running without hesitation?
And if so, do you reccommend I do it myself, or have it done at the dealer? Is it costly to pay to have it done? I've always worked on my cars, just not sure how much of a difficulty it is to do them all yourself.
To reset the computer, do I just remove the battery cable?
I really don't need to go by the digital, I can almost see how fast gas is being used. Its rediculous.
Thanks again. Nice to see theres a place to get info and so quickly!
Josh

[blazee]

It's not that bad changing plugs and wires in these. There is access through the wheel wells for the hard ones you will need some extensions and swivel though.


Just disconnect your battery cable for about 5 minutes to reset.

[BlazerLT]

Originally Posted by JoshBarber

I just bought the truck, so I havent done any of the tune up stuff yet. Do you reccommend I do the plugs and wires if the engine seems to be running without hesitation?
And if so, do you reccommend I do it myself, or have it done at the dealer? Is it costly to pay to have it done? I've always worked on my cars, just not sure how much of a difficulty it is to do them all yourself.
To reset the computer, do I just remove the battery cable?
I really don't need to go by the digital, I can almost see how fast gas is being used. Its rediculous.
Thanks again. Nice to see theres a place to get info and so quickly!
Josh

Always treat the truck like it has NEVER been maintained and do a complete tunrup with new fluids, plugs, wires, filter and the whole lot.

[JoshBarber]

Originally Posted by BlazerLT

Always treat the truck like it has NEVER been maintained and do a complete tunrup with new fluids, plugs, wires, filter and the whole lot.

So far changing the air and fuel filter made a huge difference. I do believe it was the fuel filter mostly, as the air filter looking fairly clean. The shit that came out of the fuel filter was black dirt. Never seen one so bad. Take note, everyone else with the same question. THE FUEL FILTER DOES MAKE A DIFFERENCE IN GAS MILEAGE IF ITS CLOGGED UP!

As for the plugs and wires.......it may be a little while, as we're in the middle of the second snowstorm in 3 days. 8 inches today ontop of the 2 ft from the other day!

On an up note, the 4wheel drive has been nice in the snow (knock on wood)

[BlazerLT]

Originally Posted by JoshBarber

So far changing the air and fuel filter made a huge difference. I do believe it was the fuel filter mostly, as the air filter looking fairly clean. The shit that came out of the fuel filter was black dirt. Never seen one so bad. Take note, everyone else with the same question. THE FUEL FILTER DOES MAKE A DIFFERENCE IN GAS MILEAGE IF ITS CLOGGED UP!

As for the plugs and wires.......it may be a little while, as we're in the middle of the second snowstorm in 3 days. 8 inches today ontop of the 2 ft from the other day!

On an up note, the 4wheel drive has been nice in the snow (knock on wood)

Remember your PCV valve!

[JoshBarber]

Originally Posted by BlazerLT

Remember your PCV valve!

Havent replaced it, as I popped it out, and it rattled pretty good. Should I do it anyway?

[Rick Norwood]

It never hurts to replace them with a new one. I have had a plugged fuel filter ruin a $200 fuel pump. Nothing beats good periodic maintenance. When in doubt, swap it out!

[BlazerLT]

Originally Posted by JoshBarber

Havent replaced it, as I popped it out, and it rattled pretty good. Should I do it anyway?

Always replace them. They are cheap.