So it is a couple months later and I had to fight the same problem. My 2001 Chevy Malibu fuel filter is difficult to remove. The connector is a little different than described above, but enough so that I thought to tell how I removed it. The only people who care are you who searched to find this.
The hose from the fuel pump ends at the fuel filter with a green plastic "quick disconnect." The quick did not work for me, so I finally figured out to a) open the green clip by flexing its retainer back a little and pulling the clip surface down toward the ground, and b) push the entire green plastic structure up and through the hose-end structure. On its way out the fuel filter could finally be extracted.
Finally, the newly purchased fuel filter's white clip had to be removed (it was slightly too wide) and the original green clip reused. I had to insert the green clip part way, stick in the fuel filter, then push the green clip structure all the way in.
Saturday, September 20th, 2008 AT 2:56 PM