The fuel gauge was saying emoty when at idle and about half to a quarter full while driving(it was fluctuating). I am guessing it is the level sending unit unless there is something else to try first. The haynes manual says the sending unit and fuel pump must be replaced together because they are one unit, but the parts are sold separately. Any info or help would be helpful?????

 

Unless they chagned something the fuel pump and sending unit on your '00 are the same as mine, and yes they are one unit and I had to buy them as one unit. Depending on where you go, price ranged from $260-$350.

 

just a guess.... i think it has a floater in the tank to tell us how much gas is left and i think its located toward the front or something....so when u accelerate gas gets pushed to the back of the tank and the meter goes down cuz theres less fuel in the front to keep the floater up....then when u slow down the fuel returns to the front to even out....then if u brake more goes towards the front and the gauge increases even more.....at least thats my hypothesis i dont really know how it works.....i just know when it gets close to e its time to fill up and not to stretch it too much

 

I believe it is the sending unit. I have a friend with a 2000 blazer, he said the guage said half a tank, and the blazer just quit. It turns out it was completely out of gas and the sending unit was the problem

 

yes it is the sending unit.......my truck has been doing that for like 5 months

 

It's absolutely the sending unit, you can disconnect the sending unit from the fuel pump.

 

Yea it's more-than likely it's the fuel level sensor, have autozone scan it for dtc's a faulty level sensor will usually set a P0463 in the PCM (will not turn on the Service Engine Soon light). And you can definitely service just the fuel level sensor. You have to remove the tank and pump, but you can seperate it easily and it is available from any G.M. dealer.