Farris

I have a 93 4runner 22re engine man trans. Cruise has worked perfectly until today. I started hearing a strange popping/squeaking sound coming from the firewall only under acceleration and then I noticed it was only when the cruise was set at a speed over appx 60mph. Even though it made this noise, the cruise control held speed accurately. No noise under acceleration when cruise was off. Speeds under 60mph, the cruise seemed to work fine. I have all new vacuum lines (doesn't mean there isn't a leak I know, but unlikely). Has anyone had this issue before? Is there any maintenance that I can do to that actuator, or is it likely about to go out and I just need to replace it? Thanks