Hyundai Elantra Lurches

My 2008 Hyundai Elantra supposedly had its recalled fuel pump replaced in Aug. 2008 by a dealership that has since closed. I am wondering if they ever made that repair.

Recently, when accelerating, particularly after a right turn, the car loses power, then lurches forward. The car has a slight hesitation before accelerating when the tank is full; it only does the stop-lurch routine during attempted acceleration when the tank is less than 1/4 tank full, becoming more pronounced when the tank is 1/8 full.

The Hyundai dealership that I took the car to in April assured me that the computer check showed only that I hadn’t screwed the gas cap on tightly enough. That makes no sense to me since the problem actually subsided a bit after I had last filled the tank and screwed on the cap, not when the care was doing its stop-lurch routine. I already registered a report with the Hyundai Customer Service Center.

Do you think the fuel pump is causing my car’s problems? Something else? How do I get Hyundai to actually do something about this? Thanks!