Higher octane gas is just a bandaid. These engines were designed to run on 87 octane. Alot of times the tick can be resolved by cleaning the MAF. You can find CRC Mass Air Flow Sensor cleaner at your local advance auto parts or auto zone. Costs roughly $5-6 a can and wont hurt the airflow element like carb cleaner potentially can. Just clean it every oil change to keep your vehicle running top notch.
Secondly, I would run a can of seafoam in the engine to decarbonize the intake runners and combustion chamber. Just run a can through the brake booster vacuum line. You can find directions on here by using the search function.
Third, if your problem still exists, I would look into finding a vacuum leak.
As the other guys have said, it is also possible that it is an exhaust leak. You can usually spot one by the black silt deposits around the problematic area. (collector flange, egr tube, etc..)