I had trouble with my fuel pump in my 1996 Ls 4wd 4dr for about a week and it was getting worse by the day so I pressure tested it and had to put a new pump in, problem solved with it starting, but my gas gauge still wanders.. When I take off , it will read like there's more gas in the tank than what I actually put in it, and when I start to slow down the needle goes down. Does anyone know what causes this to happen ? I was thinking maybe the gauge itself is failing but hopefully not..

 

wouldnt worry about, just movement of the fuel. same thing if you park on a hill

 

When you replaced the fuel pump, did you also replace the float that sends the fuel level? You can buy and replace just the pump or you can buy a complete assembly with a pump, wiring harness, seal, and most importantly in your case-- a float which sends the gauge the fuel level in the tank. It sounds like you didn't get the new float which may resolve the wandering gas gauge syndrome. Here's an AC Delco complete assembly from Advance Auto Parts. $319.99 in my area

https://shop.advanceautoparts.com/p/...986%7CL3*15378

Until you can do that, try this temporary tip. When you fill the tank, write down the mileage and then multiple the total number of gallons in the tank--approx. 19 times the average MPG your Blazer gets: example 14.5 MPG. Add that to the odometer reading at the time of the fill up. That gives you how far you can drive until the next fill=266. You may want to carry a 2 gal. can of gas with you just in case. Use all appropriate cautions when transporting gas!