I have 2 toilets in a 30 Year old house. Last week when I flush one of the toilets the other toilet has back pressure air. It only does this with the one way.

I have 2 toilets in a 30 Year old house. Last week when I flush one of the toilets the other toilet has back pressure air. It only does this with the one way.
You have a partial blockage downstream from the other toilet, The air you see is back pressure when the discharge hits the clog. The solution would be to pull the other toilet and snake from there. Good luck, Tom

Thanks speedball, WIll give that a try.

Let us know how you make out, Good luck, Tom