taillight problem

[Night Shifter]

so i just got a new(cleaner) set of taillights for my car and i just put them in.. after installing them i turned my lights on to make sure all bulbs and everything were working. the far right bulb was out but when i tapped on the lense the middle one dimmed out and after a couple taps the far right bulb came on.. then when i closed my door it made the middle bulb go out... so pretty much if i hit a bump in the road i'm gonna have lights turning on and off...
is this something that i may have caused or do i just need new bulbs

 

[mustang50v8]

i would say its some bad bulbs. get some new ones.

 

[Night Shifter]

does the 3rd brakelight use the same bulbs as the tails?

 

[Mustang5L5]

Bulbs are making poor connections in the sockets. Either clean the connectors, or replace the sockets if they are starting to melt and the plastic is ruining the connections