I have a 1999 Civic and twice in the past 2 weeks the window has popped out of the front rail. I put back on and it works fine. It doesn't seem loose. Should I just replace the front rail?

 

Check to make sure that the bolts that hold the rail in place are snug. also check the rubber lining in the rail cause sometimes i will bunch up and bind on the window. If both look good use some silicon spray to lube up the track and it should clear up the issue.

 

I'll try that. Thanks for your help.

 

There is a service bulletin on this complaint. I can .pdf it to you if you want.
If your car is a 99 si then it probably just needs the rubber run channel replaced to fix it for good. I think the four doors got a new regulator as well. I'd have to look at the .pdf again.