We started hearing a whistling squeak that was louder when the car was idle. Replaced the serpentine belt and the idler pulley. The car is still noisy, but more of a squeaking rather than whistle. It seems to go away once car has been running. Almost 2 days later, and the car started to jump. This also stopped after car was running a little bit. Any suggestions?

 

Did you check the belt tensioner pulley when you changed the idler pulley?

 

That's what we were thinking, but what's the best way to check it? We are new at this. Thanks for any input.

 

I'm researching, and I gathered this....
Without the belt on, you should be able to spin the pulley manually. If it spins smoothly, it should be ok. If it wobbles or is tight, then replace it.
Is this correct?

 

Sounds like the Camshaft Synchronizer, they squeek or chirp when going bad and it's right above the waterpump, makes it sound like an idler wheel or waterpump, If it goes out it will trash the motor, metal fragments everywhere in the motor. I had to replace mine right after i bought the car, a friend who knows mustangs told me and i bought one for 70 dollars, installed it and been great ever since.

btw, the camshaft synchronizer is a common failure item.

 

Thank you for the info. I will look in to that!

 

any update on the progress with your problem?