97 Silverado Z71 Vortec Fuel Gauge Problems
 

Hi, I'm new here and performed a couple of searches for information on this to no avail. I saw some similar problems but nothing exact. If it's been addressed before, shoot me a link and I'll be on my way.

For years, my fuel gauge has bounced up and down as the truck moved down the road. I figured it was the sending unit and that it was a pain in the neck to get to, so I let it ride. My fuel pump went out a couple of weeks ago, so while they replaced it, I had the sending unit replaced as well. I got the truck back and the gauge continued to bounce and may have even been worse. The shop takes it back and works it over again.

I get it back and the bounce is gone! It was at about 1/4 tank so I fuel up, filling it up. I get in and notice that the gauge is still at 1/4 tank. I turned the key on and off several times with no change. I start it, ease forward and brake hard, hoping the float is just hung up in some way. No dice. I take it for a spin and notice no difference when making turns, but when the truck bounces a little bit vertically, the indicator may creep up a notch or two on the gauge. It doesn't move unless I have some vertical movement. I used a speed bump in a parking lot and the gauge finally rose to just below the full line when it wouldn't go any higher. In the past, a fill up would have put it just past the full line. Even when it bounced, it hopped straight to full when I filled it up. Also, when I turn the ignition switch off, the gauge quickly rises to 1/2 full which is what it always did in the off position.

So, long story short, the fuel gauge used to bounce. Fuel pump quit and was replaced along with the sending unit. Gauge still bounced. Shop worked on it again and now I have to bounce the truck to get the gauge to rise on a full tank of fuel.

Any ideas?

Hmm... any idea what the shop actually did... maybe they did something, saw it stop wiggling, and assumed it was displaying the correct fuel level, when in reality, broke it entirely?
While I've never had an issue similar to what you are describing, that does seem to be a common problem and most of the times never seems to be resolved on forums. People just ignore it for the rest of the lifespan of the truck. Sometimes they replace the fuel pump and sender unit and it fixes it. Sometimes they replace the gauge cluster and that fixes it. Sometimes neither of those actions resolves the issue.

Sorry, I forgot that part. They said it was a loose ground causing the motion and that the hole for the screw was stripped out. I'm not sure how that happened, since it has never been touched, but I guess it could rattle loose after 18 years. The put a larger screw in and that took care of it.

Or so I thought.

Within a day or so, it sprouted a leak, presumably from the top of the fuel tank, oh and the bounce in the gauge has returned. It goes back and gets another new sending unit. Once again, it bounces. I think it is safe to rule out a sending unit as the problem. Is the cluster the next guess?

All right, I guess I am down to the nitty gritty and have the same problem pretty much everyone else had had with this make and model. Does GM part/kit #12167652 still exist anywhere? I have hit several sites and they all say "discontinued" and "not available." I am just at a loss as to how this worked fine for many years, then quit and now apparently can't be fixed.