Hi,
Did the mechanic point out where exactly in the throttle body the leak could be? My Adub had the same issue and it was a combination of underfilled cooling system, incorrect spark plug gapping, vacuum and sc boost leak causing it. I had someone give me similar advice and found it to be way off. This stuff can gum up the works and doesn't solve the cause of the issue, just bandaids it temporarily.
I would first check for a vacume leak as that is a very common cause of this on these engines. I would also check the ECU for error codes as there could be issues with the TPS, O2 and/ or air flow sensor that would also cause this. This is really easy to do on these engines as all you need is a wire to bridge a connection between 2 terminals.