I have reviewed the previous answers to this problem regarding a blocked vent. However, I have 2 toilets and 1 vent. 1 toilet is fine the other drains. Also,in the bathroom with the problem, the sink gurgles when you drain it. I have,on three occasions corrected the problem by shooting water from my water hose down the vent pipe but days later the problem returns. Any ideas? Thanks in advance for your response

The fact that both toilets are on the same vent is why only one is affected. The siphon/suction is only going to go the least restrictive route. One toilet has slightly more suction so it drains while the other has had its suction removed by the other toilet draining. The gurgling also tells me your vent needs to be rodden. Rod from the roof to the basement floor plus 20' more. You might find it helpful to rent an electric sewer rodder.

I have,on three occasions corrected the problem by shooting water from my water hose down the vent pipe but days later the problem returns. Any ideas?
You have a partial blockage in your vent. Running water down it may wash a small bit away but to do a through job follow Ballengerb1s advice and rfent a sewer machine and snake the vent. Good luck, Tom