I drive a 2000 Z28 and after about 40,000 miles there is now a considerable gap (about an inch or so) between the fender and the door and the fender is pulled out some. Is this a common problem and is it easily fixed? Or will I have to replace the entire fender...

 

I'm assuming you've jacked up your car from the corner of the body right behind the front wheel well at one point?

This happened to me a while back after jacking the car, all we did to fix it was place the end of a 2x4 up against the underbody fender panel lip near the jacking point under the car and whack the other end of the 2x4 with a mallet/sledgehammer. This will pull the fender back into the body and flush with the door.

 

I didn't jack my car up at that point, but I will definitely try your suggestion, thanks.