Floating Fuel Gauge
 

Hi. I know that Blazers are notorious for floating fuel gauges...and mine is no exception. On my 01', my gauge floats very erratically. Even to the point to where my low fuel light comes on. I take it this is the sending unit that plugs in to the top of the fuel pump itself? Can this just be replaced or do I need to change the entire unit all together? Thanks.

The fuel level sender can be replaced separately. AFAIK, the part is available only at a GM dealer.

what he said^ but honestly might as well buy the whole pump/unit. they are notorious for going out and ONLY buy delphi or delco units,and its not too much more.

Win,win situation.

Check your ground wire too.

I'm having this problem with my 01 as well. The fuel pump was replaced at a shop a little over a year ago but I have no idea whether the sending unit was replaced as well. I'm assuming the tank would have to be dropped to get to it right? Besides a faulty ground, is there anything else that could cause this besides a bad sending unit? The problem has gotten worse lately to the point I'm not ever really sure how much gas I have in it unless I fill it all the way up. When this happened in the past I would just shut the vehicle off and then start it back up and it would be fine.

Could be poor a ground connection, or bad level sender. Aftermarket fuel pump modules use an el cheapo buffer in the fuel level sender, which causes the gauge to be inaccurate, & fluctuate. Along with countless other problems with aftermarket fuel pump modules, this is another reason to use AC Delco or Delphi only.

What brand pumps came in the Blazers to begin with? The reason I ask is that several people are saying to only use Delco or Delphi. I think I'll take my chances with the one that didn't originally come in the truck.

Depending on the date of manufacture, OEM was either AC Delco or Delphi. Both are built to the same specs. If you're planning on selling the vehicle, aftermarket might be OK, but don't wait too long;). Longevity is anywhere from zero to a couple of years. Don't expect to get 100K miles out of it like OEM, they won't even come close.

floating gas guage
 

I know it's going to add cash to the job but I suggest changing the fuel pump along with the sending unit. reason? murphy's law will kick in and within a month the fuel pump goes after disturbing everything on the fuel tank. anyone agree?

Blazer47, you are correct. Also, and I know a lot of members will laugh at this, put some silicone or RTV on the wires around the pump and sender if you live out in the rural areas. I filled my Blazer up an drove home.Went to start it the next morning and the Low Fuel light came on along with no fuel gauge deflection. Made appointment to see my mechanic in town in 3 days as I knew tank would by about 1/4 full. Yep rodents had eaten the wires on the top of the tank. Do the same under the hood.