Antenna needs grease and servicing, suggested every 2 years if it rains a lot. Probably your antenna has never been serviced. It comes apart and it's pretty obvious where to grease. There is a recent forum post that goes into a lot of detail. If you have an original antenna, be aware that this is a $1000 replacement unit, so treat it well.
Vacuum leaks in the door, trunk and gas flap happen from rubber seals that dry out. The originals seem to last about 20 years or so in California weather. Any leak causes all doors, trunk and gas flap to stall and take a long time to lock, if ever. You can sometimes hear the leak. Put your ear to the center of the trunk lock, to the inside of the trunk on the gas flap side and to each door from the inside as you try to lock the car with the remote or pressing down the driver's lock.
Another tip is to try to start the lock sequence and then press each door lock down one at a time. If one door has a leak, once you press it down, the other doors could immediately lock. Then you know that one door needs a replacement vacuum element. Of course if you have multiple problems, this test may not work well.
Good news is antenna service is maybe 1 hour's work. The antenna push rod and long tail can be replaced. Watch out there are two types and you need the one that is right for your antenna.
Also changing a door vacuum element, can be 30 minutes work if you know how to carefully open everything and it's even faster switching either trunk or gas cap elements.
I don't think it possible to repair one with the seal cracked, which is a pain, because obviously otherwise they work fine.
Hope that helps.
