Wild Yeast Sourdough Bread

I have been working with my sourdough starter for a few years. I began with a recipe using the starter and commercial yeast. This year I got adventurous and decided to only us wild yeast for my sourdough bread. I worked with a few recipes without much luck then I decided to take a few tips, hints, and prcedures and use what I alreadty knew and came up with a recipe that I thought had been tweaked and "perfected". I made 3-4 batches of breaqd with this recipe and each adn every loaf came out beautiful. Since the last successful baking I have ran into dough that won't become fully elastic thus during the long rising time the top or crsut if you will begins to tear apart just at the top. I have kneaded and kneaded and made sure I had ample enough flour for the mixing stage. I have kneaded for a total of 30 minutes or more with resting time in between each kneading which last for about 10 minutes and the rest period generally lasts for about 10 minutes. The bread not only looks unappealing when it dos this but the tesxture on the inside is not light and fluffy and sorta dense like quick bread. Below is the recipe I use:

1 cup starter

2 tsp. sugar

1 cup flour

1 cup hot water (100-110 degrees)

Mix together in a bowl and cover with a
towel overnight.

1/3 cup oil

1/3 cup sugar

1 tsp. salt

3-4 cups flour

Mix together until you have firm dough. Knead on
floured surface until dough is elastic. 22-32 minutes, kneading in increments
and resting for 10 minutes between each kneading. Rise at least 3-4 hours or
until doubled in bulk.

Any help or tips is greatly appreciated.

Thanks

Doug