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Hello, it is most likely that the thermostat is going bad, best to replace in that case.
We can however do a few tests if you like, tell me a lot about your technical skills so that I can coach you on that... and later if needed on the correct replacement that works with your type of system.
We can go from there.
Good work! So far in my 55 years in the business I have not seen a thermostat benefit from being blown out with air... there is always a first... get back to me if that does not solve the problem permanently.