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1999 GMC Sonoma


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Anonymous Poster
dabatty@charter.net

Dec 3, 2008, 8:51 AM

Post #1 of 5 (3852 views)
1999 GMC Sonoma Sign In

My 1999 GMC Sonoma pick up just lost gas mileage from 350 miles to a tank of gas to 100 miles to a tank. I do not have a gas gauge so I use the trip mileage to keep track. I filled up and reset the trip meter and ran out of gas at 112 miles. Usually can go over 350. What could be wrong?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 3, 2008, 9:05 AM

Post #2 of 5 (3844 views)
Re: 1999 GMC Sonoma Sign In

Gotta ask - Did you truly run out - that perhaps only known if you filled it up?

That's an extreme change in fuel consumption that would almost certainly show up as not running well in some way.

Still need to know if it really ran out from full to just 112 miles then I'd check fuel pump for sounds, pressure, connection wiring right at it (common problem area) and it may need a new pump and or the wiring there - fix the gauge and the pump at same time,

T



Guest
Anonymous Poster
dabatty@charter.net

Dec 3, 2008, 11:05 AM

Post #3 of 5 (3840 views)
Re: 1999 GMC Sonoma Sign In

I filled up in St Louis MO and ran out just outside of Columbia MO. I got 2 gal of gas and it started up. Went to Columbia and filled up and it took the normal amount to fill from an almost empty tank. Any other ideas?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 3, 2008, 1:09 PM

Post #4 of 5 (3833 views)
Re: 1999 GMC Sonoma Sign In

There's a couple clues here and some info needed still. Just how many MPGs is this now adding up to?

2. Is it running properly? Leaks, smells - anything wrong with the way it runs - check engine light etc., as I'm also not ruling out that someone MIGHT have stolen some fuel on you. What's worse if that happened is now we're on a goose chase for a problem that might not exist other than a theft!

* What's confusing is if it runs properly then why this dramatic difference?? I could suggest that there was a fuel injection problem, tune-up items - all sorts of things but you'd be complaining about it running lousy too AND a CEL would almost certainly be lit.

What's the story with the fuel gauge not working - anything unusual there? It could be a plug right near the gas tank that can get wet and cause problems with either gauge or fuel pump. Other than gauge not working the pump must as you are using it.

** A maybe - The fuel filter is usually place on the frame rail on this vehicle and the line and flare nuts or the dang filter itself can get rusty. Some are a mess just to swap a fuel filter and if rust is an issue I've seen even the body of filters rust and leak! I might only be noticed when engine is running at some way that YOU don't see evidence without taking a direct look at the lines and filter.

Just a note on running out of gas: Fuel pumps really don't like that as the fuel itself helps them run cooler and they last longer when not allowed to run too low or worse run out. I can see why you got surprised if this thing holds some 30 gallons and is OUT in 100 miles. That much consumption simply has to be somewhere!

Has it demonstated this level of consumption again? If not than what happened? Someone reset the trip meter on you or took some gas?? Not sure what else to say till I hear back....

T

Ps: I have the habit of resetting trip meter on all vehicles I use when they are filled and think that's a good general idea - just a glance at the gallons and miles you went tells you about what you got for MPGs AND if I ever see one of my own still reading full or something with a couple hundred on the clicker than I don't trust the gauge

..........



Loren Champlain Sr
Veteran / Moderator
Loren Champlain Sr profile image

Dec 3, 2008, 5:39 PM

Post #5 of 5 (3828 views)
Re: 1999 GMC Sonoma Sign In

First off, if your fuel guage isn't working you should have a check engine light on with a Fuel level sensor code set. If your CEL has been on because of this, you won't know when something else takes a dump. The 4.3 Vortec engines have a problem with the fuel feed lines leaking. I'd get the sender replaced, then check CO levels. Not something to 'let go'.
Loren
SW Washington






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