Chevy Tahoe Gas Sensor Problem

I have a 2003 Chevy Tahoe, automatic transimission. Lately, when I have a 1/4 tank of gas or a little bit above, it tells me I have like 90 miles to go until I am empty, the check engine light comes on and then the truck begins to sputter and fail, like I am running out of gas. But keep in mind it just told me that I had over a 1/4 of a tank left. I think the sensor is bad (if that is what you call it). Have you heard of this problem before and if so, does it cost alot to replace?

Thanks!
:D