I replaced my fuel pump in my 97 4 door LS blazer a few weeks ago and right off the bat saw my fuel gauge was off. When i did the instalition, i had about a 1/2 tank of gas. my gauge reads about 1/2 tank to a 1/4 tank of more gas than it really does. it does work just not accurate. do i have to reset somthing or did i mess somthing up. eveything went in fine and i didn't break anything. so could you guys help me out, thanx

How is your fuel level sensor? I had mine replaced and it eliminated this problem...truth is it's not a big deal.

I replaced my fuel pump in my 97 4 door LS blazer a few weeks ago and right off the bat saw my fuel gauge was off. When i did the instalition, i had about a 1/2 tank of gas. my gauge reads about 1/2 tank to a 1/4 tank of more gas than it really does. it does work just not accurate. do i have to reset somthing or did i mess somthing up. eveything went in fine and i didn't break anything. so could you guys help me out, thanx

I had the same problem when I replaced mine.
It turns out the KnuckleHead at Napa sold me a pump for an S10, not a Blazer. The S10 was a taller unit with a longer arm on the level sensor,and my truck would only register full for about 5 miles.
Had to drop the tank again and re-install the correct unit.
It's also possible you may have gotten a 2 door pump assembly.
The tanks are different on 2dr and 4dr models.
I'd check the web site of the place you bought it from to compare part numbers (that's how I found my problem)

If you have the correct pump, I'd guess your level sensor arm is bent.