I had the same symptoms with bad reception that you describe.

THEN I FIXED THE PROBLEM!!!

Now I have reception that is as good as every other car radio in this area (including a supertuner I had in a different car). If you read the post from ddalder, you could most likely find the problem and reception issues will be gone.

I assure you my expectations are not low. I have no doubt that I am far more competent in how an audio system is supposed to perform than the average GM mechanic.

The antenna system in these cars is quite sophisticated. The solution is NOT to throw the baby out with the bathwater. Catywompi'* system appears not to be operating as it was designed, so let'* put the effort into getting it operating properly rather than throwing it away and starting over.

One question that I don't believe has been answered yet is whether the stock head unit has been removed and reinstalled or if there has been any other work done in/around the antennas (windshield replacement, etc) or other audio components. I know you are waiting for a more opportune time to assess this so please let us know when you are able. Also, how long have you owned the car and has the sound quality been the same from day one.

when I got my car I left it at a place to get new tints, because the ones that came with it were damaged. the person who changed my tints scraped the back window with a blade to take the old tint out. After that my reception got worst. thas when I noticed what had happened. You can tell that the metal got scraped out of the window because the lines look diffrent where the blade was used. If I remember correctly they look more orange.

Again, please keep opinions of eachother out of the discussion.

I did find the problem, it was a combination of the stock stereo having a poor tuner and the antenna being in the windows, as direct to me by my Pontiac dealership and several other radio experts. My reception issue was gone after i replaced the stock stereo with one that has a better tuner.

This is really bad news. First of all, tint can definitely have an adverse affect on the antennas. Some have experienced little or no problems, but I've spoken with many who have had noticeable problems post tint. The worst part of this is that the window was scraped with a razor blade to get the old tint off. I suspect the antenna was damaged in the process. Antennas aren't just a piece of wire. These are engineered components designed and tuned for specific frequencies. This could get costly and I'd be going after the shop that did the work. The antenna in the 2K+ Bonnevilles can't be replaced on its own. This requires a new rear window.