Mix the graham crackers, pecans, and 1/3 cup of sugar in a bowl, and mash the softened margarine into the crumbs until thoroughly combined. Press the crumb mixture into the bottom of a 10-inch springform pan. In a bowl, beat the cream cheese, 2 cups of sugar, eggs, and lemon juice together with an electric mixer set on medium speed until fluffy and well blended; spoon the mixture on top of the crumbs.
Bake in the preheated oven until set, about 1 hour and 10 minutes; remove from oven, and let cool for 30 minutes. Mix the sour cream, 1/2 cup of sugar, and vanilla extract together in a bowl; top the cheesecake with the sour cream mixture. Return to oven, and bake 10 more minutes. Allow to chill in refrigerator at least 4 hours to set.