Hello, I am new to this forum and hope I'm posting in the right area. So yesterday I bought a new to me 07 z71 4x4 tahoe with 100k. I love it! It's very clean and was well kept by the last owner. Tonight when I started the truck after leaving the store when I accelerated I would get what sounded like a horrible metal on metal chirp. I couldn't figure out where it was coming from. But it only did it when I was in drive and on the gas. If I let off it would stop. I pulled over l, turned the truck off and back on after I drove 5 mile and the noise was gone. .. should I be worried? Does anyone know what the problem could be?

 

Just took it to my mechanic. It's the catalytic converters.... pretty expensive fix.

 

I have never herd of a Converter "chirping" !
Get a second opinion.
Sounds more like you have something rubbing against something it shouldn't.

 

I'm going to make a prediction that your still going to have the chirp after that mechanic rips you off after putting new cats on your Tahoe.

 

I agree with SWHouston..Get a second opinion!!

 

Thanks for the advice everyone. I got a second opinion and they said it could be a pully in the motor. It would be 1000 to fix. But they recommended to buy a new one for 3500 becsuse it comes with a 100k warranty. I think I'm going to wait it out and see what happens. It has not done it at all today. Both mechanics said it "could be". So if the sound comes back I will bring it in and see if they can get a proper diagnosis.

 

Sounds to me like a bad tensioner pulley? GM tensioners are notoriously high fail items, especially if a mechanic gets to aggressive when replacing the serpentine belt.. Find out if the belt was recently replaced, if so might be a good place to start?

 

OMG, the mechanic recommended a new motor based on a noise you heard that went away? Amazing

 

A grand for a pulley? Rock Auto sells the AC Delco one replacement for $49?

 

Mileage is not excessive, I would have someone check the driveshaft for a bad universal joint. They will have a churping noise similiar to what you described. A good mechanic will know what to check, JMO and good luck. Keep us posted.!!!!!!!
David g.