Gas gauge acting funny

Damien05

Original poster
Member
Apr 23, 2012
3
I have a 2002 envoy. So after I cleaned my throttle body, and wow did it ever need it, my gas gauge is acting funny. When i first start it up, it reads what its supose to. Then once i put it into drive and drive even a foot, the fuel gauge reads almost empty and my range goes to 30km. Then when i put the envoy into park and sit for a couple seconds its goes back to where it was and so does the range on the dash. Then i can put it into drive and its fine, until i shut it down and start it again and it does the same thing. Ive done some searching on this and some say it could be the fuel sending unit is either going or is just gumed up with deposits. Do you think that could be it, or something else?
 

SAR85

Member
Jan 31, 2012
74
It could be the fuel sending unit or possibly the stepper motor for the gauge. You may be able to use a high-end scan tool to diagnose the fuel sending unit.
 

JerryIrons

Member
Dec 20, 2011
434
You can try running a bottle of chevron techron through it, sometimes that helps with any deposits.

Otherwise my guess would be your sending unit is starting to go bad. When my first one went bad it just stuck on E. When the 2nd one went bad it would bounce around like a pinball sometimes.

Probably now would be a good time to track how many miles you can go with a full tank... :smile:

-Jerry
 

Mooseman

Moderator
Dec 4, 2011
25,317
Ottawa, ON
Yep. My guess is also the sending unit. These are notorious for wearing down the fingers and intermittently contacting the rheostat, which is why sometimes it shows empty and then suddenly registers something.
 

Damien05

Original poster
Member
Apr 23, 2012
3
probably a stupid question, but if it shows empty for long enough will the engine shut off cause the computer thinks the tank is empty? Or will it just run so long as it has gas?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
The engine never takes action for a low fuel or oil pressure sensor report. It just gripes at you.
 

Damien05

Original poster
Member
Apr 23, 2012
3
the roadie said:
The engine never takes action for a low fuel or oil pressure sensor report. It just gripes at you.

Right on, at least i can still drive it and just go by the odomiter for fuel level until i get it fixed. Thanks.
 

tom1999d

Member
Apr 24, 2012
32
For 05 -09 Envoys & Trailblazers with less than 120k miles there is a TSB where GM will split the cost of a new sending unit. Check with your local GM dealer service advisor.
 

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