I have a 2000 Chevy Blazer 4wd V6 Vortec, I bought this vehical from a used car dealer and they had to replace the fuel pump. Ever since they replaced that, the fuel gauge has been jumping from empty to full.

When I turn the vehical off and get out the fuel gauge jumps up to 3/4 but then jumps down to empty when I open any of the doors, and then jumps back up after I close the doors. While I am in the vehical with it turned off, I could go to adjust the power seats it jumps from 3/4 back down to empty.


If anyone knows what is causing this please let me know I don't want to start on taking anything apart untill I could pin point the cause.


Thank you

 

i had this issue, but it got fixed once i replaced the fuel pump o.O

 

Quite possibly was replaced with an aftermarket brand gauge rather than AC/Delco. Try this article:
98+ Fuel Gauge Diagnosis

 

I'd take it back to the dealer & say fix it right this time.
That link rridle posted is good, but IMO it should be the dealerships issue, not yours.

 

Ok update on the topic. I took the battery cable off and checked the gauge it stayed at 3/4 of a tank, then i hooked the battery back up and started the blazer. Then I got under the truck and unhooked the cable to the sending unit it stayed below empty. With the sending unit still unplugged i turned the engine off and pulled the key out the gauge jumped back up to 3/4 and also the temp gauge jumped up. The same thing happened like i mentioned in the first post, I open the door and both of the gauges jumped down.

 

I'm going to recommend something to you that I just did on my 96 blazer. Put 10 gal of gas in and dump in a 20oz bottle of royal purple MAX CLEAN. i had the same problem and tried that. Half way thru that 10 gal. My gauge started working great. The sensor gets a buildup on it and causes erratic readings.
The max clean cleans everything in ur system. It's awesome. 16 bucks walmart. Worth a try.