When I flush my toilet big air bubbles come up and the toilet has difficulty flushing completely. What is the reason for this and what should I do to fix?

I hope someone can help me.

Thanks,

S

Sounds like you have a blockage, try plunging it, if that doesn't work, try a closet auger.

You do have a blockage, if plunger would not help snake from the roof vent, and add 15' to 20' feet more when it reach the floor, good luck.

John

I agree with both Puff and John.
However, Since bubbles indicate a blow back after the discharge I think the blockage's farther down the line in the branch so I'm not too sure a closet auger would reach it.
Since there's no complaint about a tub or shower back up the blockage may be up stream from them.
If this would be my call I would pull the toilet and snake from there. You now have three solutions to choose from. Good luck. Tom