i have a 99 blazer.tonight i was replacing vaccum lines.(trying to fix my vent problem)when i noticed the fuel guage kept jumping from e to full constantly but it wasnt smooth.it would go up and stop at say 3/4 the godown then back up and so on.i shut it off and restarted it and it was fine.tried to get it to do it again but it would'nt.i replaced the fuel pump twice about a year ago.(first one had bad pressure guage).any ideas what would have caused this?

 

fuel guage was constantly moving.if i had a half tank it would go from the half to full and everywhere in between pausing only for a second in every spot.i disconnected lines and it went full which gagrage said it should.rewired all connections and still did it.called garage back(the guy always trys to help out before i take it to him.)and he said the fuel level sensor in pump assembly probably bad.its been 1yr. and 3 weeks since i put new one in but auto parts store said they would get me another one for free.this will be third pump in1 yr. and six months.second pump bad fuel pressure sensor.2 weeks old. garage said its rare to get one to last as long as originals.why!!hopefully tommorow this will fix problem.let ya all know.

 

*Combined related threads.*
Were the pumps either AC/Delco or Delphi? Those are the OEM pumps and we have talked many times here about other brands not cutting it.

 

I agree on the fuel pump, go OEM or Delphi.
What are your vents doing? You may need more then just new vacuum lines.

 

yeah it said oem on box but i forget the name. used the box to send old one back in. the pumps are holding up. the sensors in them are not though. i go the vents working now. must have been one of the lines that didnt look to bad. now i have the abs light. i think its the wheel speed sensor on the bearing i just replaced. (looked up on here.) thanks for the help. next time i will have to try a delphi pump i guess