I start my Impala with no problem - there is something going on like the engine is shifting into place - then a loud squeal for no more than 15 seconds - then the car is fine - drives fine - no other issues. It is starting to do this everytime I start it. The dealer said it was the Air Pump. Spend $626 and the problem is still there. They changed some hoses but can't seem to diagnose the problem. No codes come up in message center.
Starting Noise on 2000 Chevrolet Impala
Problems with the air pump on your 2000 Chevrolet Impala are not uncommon. In most cases the problems are caused buy water intrusion into the pump assembly. The hoses that were replaced along with the pump are designed to help eliminate the water intrusion issue. The air pump runs on initial start up for a short time - but apparently this was not the cause of your noise. Unfortunately your problem may need to be re-diagnosed (by the dealer or someone else). It should not be to difficult to properly diagnose a nose that occurs every time you start the engine.
I have the same noise with my 2009 impala now along with now a different noise not as high pitched now the whole time my engine is running