Squeaking noise

Ok. Seriously now, maybe a vacuum leak? Could you do a YouTube video to share the actual squeak with us for a better guess? 🐁 🐭
 
He is likely correct- vacuum hoses get brittle- it can also be a solenoid- like the one on the left inner fender- some lines are hard lines, and they can be deceptive- soft lines can get hairline splits or hard at the connection-

Go slow and use a light- might be good to have someone kill the engine with you outside with the hood up to help locate.