I have a 2000 LeSabre 3800 with a noisy problem. While attempting to start the engine with starting fluid the intake manifold exploded like a hand grenade and shattered into a thousand pieces. I replaced the manifold and now there is a “huffing squeak” that develops when the car warms up. This goes away under engine load and returns at idle and any time the car is not accelerating. I have replaced the water pump and EGR valve. The check engine light turns on and off all by itself. Since the manifold shattered could there be pieces in the EGR system?
God only knows what went where. Can you isolate the noise somewhere in the engine bay?
Here’s the thing: all of the vacuum components that are connected to the intake manifold took the full force of that explosion, so I’d start by checking every vacuum line and whatever it’s connected to.
Good luck with that, and let this be a lesson to anyone reading that in a fuel injected car, if it won’t start with one shot of starting fluid, it’s not going to start. Period.