Chirping or squealing noise from left side of engine

I had recently had a tuneup at one of the shops here, before tuneup (no noise) after getting tuneup, plugs, fuel filter and etc, I drove car home, put in garage for a week or 2 until I could drive again due to work schedule, upon cranking car in garage, after a few minutes I heard this chirping or squealing sound, I took car back to mechanic, they said it was coming from left side of engine, took to dealer immediately and they said it was water pump, I had all the idler pulleys and serpentine belt replaced due to mileage, and AOS valve, the dealer originally said it was the water pump. I had mechanic check pump, he said with the belt off pump that it was coming from left side of motor, upon further investigating on Porsche website, I discovered by other people that had same problem that it was probably loose spark plugs, since noise was just coming from left side, and I did not have issue until after getting tuneup. Have u had any problems like this before
I am trying to give u all the specifics, the Porsche site said that it could be the idler pulleys, water pump pulley, serpentine belt, AOS valve, motor mounts, or loose spark plugs, done everything except last 2
can u think of any other cause of this problem

Thanks
Terrell Alexander