Have the wheel bearings checked, as well as the alignment.
Get your wheels checked
The factory size is: 225/60-16
Have you checked your tires?
they are not balanced properly.
Listed on the driver's door post.Original Equipment Size: 225/60-16
Likely a bad tire or at least that's the first thing to check
Have the head gaskets checked and intake manifold gaskets checked for leaks. The 3.4's are known for head and intake leaks! Or a bad thermostat.
Normally this is caused by one or more of the tires out of balance. If the steering wheel is shaking then you know it is a front tire. Have all your tires rotated and balanced.
First check your brake fluid level and if full you need to have the ABS wheel sensors checked out for a bad one.
I had a problem with stalling with a 2000 Impala, and it was the oxygen sensor.
Impala HQ .com
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