1999 K1500 Suburban Gas Gauge Oscillating

[ts18997]

I replaced my fuel pump last March. Have had no issues with it since then and the problem I had back then was corrected. Starting about two weeks ago, noticed the needle on the gauge ocillating very fast. The needle will jump around way more than it used to and it is moving in place so fast that it actually looks blurry. It is keeping accurate level of what fuel is left in the tank. When the vehicle is turned on, the needle slams all the way to the right and they goes into the ocillating mode. Does this sound like the gauge itself or the sending unit which is on the fuel pump I recently replaced? Grounding issue? Thanks.

[G.A.S.]

Originally Posted by ts18997

I replaced my fuel pump last March. Have had no issues with it since then and the problem I had back then was corrected. Starting about two weeks ago, noticed the needle on the gauge ocillating very fast. The needle will jump around way more than it used to and it is moving in place so fast that it actually looks blurry. It is keeping accurate level of what fuel is left in the tank. When the vehicle is turned on, the needle slams all the way to the right and they goes into the ocillating mode. Does this sound like the gauge itself or the sending unit which is on the fuel pump I recently replaced? Grounding issue? Thanks.

.

I would start with the plug in connector at the tank.
make sure the (terminal) is clean. inside ond out.
Ground very well could be the issue and If I am not mistaken, there is a ground wire right in that clusters plug.
If not, You should have seen it when you did the pump.

[wafrederick]

Needs a sending unit and GM has a problem with them in their cars and trucks.I believe you can get just the sending unit itself from the dealer and you need your insurance slip so the dealer can order the part going by the vin

[rockwood84]

yep still a ground problem.

[G.A.S.]

what did you find?

[777stickman]

My '98 Sub K2500 7.4 was and is still doing exactly the same thing as yours. 1 1/2 years ago I replaced the pump with an AC-Delco pump assy matched to the VIN. I had absolutely no issues with the electrical connections at the tank. Pulled the ground off the cross frame and cleaned it. No help with the gas gauge vibration.

My suspicion is the gauge itself as there have been previous posts suggesting the same.