I have a 2004 LS 4D 4x4 that when you start it up the gas gauge stays on empty with low fuel indicator on.. if you keep running/driving it for a minute or 2 it kicks in and reads correctly until you shut it off again.. then it is rinse and repeat. I've tried smacking the dash a little to see if it might be a loose connection, but it doesnt seem to matter. doesnt jump or kick in from doing that.. Any ideas?

 

Either your dash cluster is slow to respond to the signal from the tank or the signal from the tank is slow to reach the cluster. As long as it's somewhat correct the other 95% of the time I wouldn't worry about it. I've had several of these S series over the years and every one of them has had some strange quirk about the gas hand. My Blazer reads a tick below full right after filling up. Always has. My S 10 shows a tick past full on fill up. Always has. Just one of those personality things with your particular truck. If you were to replace the pump assembly with a whole new unit it might do something different. But that would be a lot of trouble just to correct a slow gauge response.
Just my 2 cents.

 

Yeah, I really did not want to pull that pump assembly out and change the float sender if I did not have to. I'm just wondering if there was a easier way to test the cluster and sender to narrow it down. I may be getting a part Blazer in a day or so. Maybe i'll swap out the cluster and try that.. Should be able to do that right? mine is over the 200k miles mark so the state doesnt require it to be correct at this point.

 

As long as it has the same gear shifter you should be able to swap the cluster. Floor shifter equipped trucks won't have the gear selector display on the cluster. Obviously manual trans won't either.

 

It could also be that the variable resistor on the fuel pump assembly is tarnished or it's going bad. I ended up replacing the whole pump in my 2002 LS, and that resolved the fuel gage issue for me.

 

It's the sender in the tank.. rock it back and forth and the thing works and fluctuates with the gas waves. changing out the pump in a few days. can't handle having a broken gas gauge.

 

I replaced the original pump on mine and it still does this. However, I will say my gauge for the most part is accurate. It will just stay after full or on full after a fill up and will only start to move after it's close to a half tank.

 

well mine just sits at empty unless i sway left and right a few times in the drivers seat.. Hmm that sounds bad.. no I'm not a big guy.. 170lbs, but any rate.. a few shakes and it springs into action. tomorrow however I intend on changing out the pump. have the replacement out of another blazer and it seemed to work before i pulled it. Hoping this will fix it up. I can't have it hit and miss. oddly if i know something is broken, I fix it. No ABS lights on, No Check Engine lights on anything i own...

 

Don't brag Murphy's law is always a factor

 

Oh yes, you are issuing a clear invitation to the dance with that statement 😮