use port 443 for VIP and pool members

inline.

2. Do you have multiple traffic groups enabled? 
>> can explain bit or example pls? 

What BIG-IP version is this? In 11.x you have the concept of traffic groups that allow you to bind different services into different service groupings that can move between HA devices.

3. And if so are you sure that the 443 VIP is alive on the active unit (vs. the standby unit)? 
>> yes, 445 VIP is alive on both units. In addition, i found the nodes connectivity (health monitor status) up and down status very frequently. 

That may be a tell-tale indication of the problem. I'd start troubleshooting this health monitor.

4. When you disconnect the active unit, do you see a failover event in logs or any indication that the VIPs are being enabled on the standby unit? 
>> there no failover occurred. I still can access using port 443/80 VIP when disconnect LAN cable for active unit. this is the additional 3rd VIP created in f5 unit...(in active-standby mode)

A failover event will get logged, and you'll see an active unit go to standby in the GUI (and a stanby unit go active). Do you not see these things when you disconnect the active unit? It could be that what you think is the standby unit is actually the active unit, or perhaps that your HA is misconfigured and both devices are active.