2002 SAAB 9-3 Covertible

After several short trips car sometimes won't start until after 3-4 tries and gets worse each time. No noise, sometimes clicking, radio and dashboard lights work, battery has been tested and changed, 2 new starters put in. Does not start in neutral either. Does not happen after sitting overnight or at work. If it gets to the point it won't start at all, a battery jump helps. Airgag light came on recently but went off after this problem happened again, starting after 4 tries.