When the commode is filling with water, it bubbles several times. What causes this? Is there a fix?

Hey Brad, Do you mean it bubbles up in the bowl? If so, not to worry. The bowl's filled by that little 1/8" tube that hooks over the white overflow tube. There is a small amount of air trapped in the overflow tube that is pushed out into the bowl by the incoming water. It doesn't hurt anything and and you would have to tear the toilet apart to fix it. If it bubbles in the tank then you have a cold water line that's captivating back down the line and inserting air in your lines. Good luck, Tom