Hello all, new here and thanks in advance for any helpful information. I have a 2002 Grand Prix in excellent shape. It has 95000 miles and runs like new. Very well maintained. The sun roof was sounding a little slow when opening. I did a complete cleaning and lubing of the tracks. This is the 3rd time this has been done since new. It makes a more than normal popping sound when first opening from completely closed. The seal on the glass is in great shape and always lubricated. Just wondering what is causing the loud popping sound. Thanks