i did two oil changes with in 1000 miles of each other to try and fix this problem and through in lucas oil treatment but didnt work..

 

You have isolated it to #6 so I would inspect the intake spring very closely. If the spring has lost tension it could cause the valve to hang while the engine is cold. I would rather have a bad spring then a bad lifter. Good luck...

 

so i a bad spring and or lifter will cause and misfire and backfire in to manifold?

 

If you have a backfire into the manifold the only possoble way for that to happen is to blow past the intake valve. Which indicates to me that the valve is hanging open until the engine warms up. My guess is the intake spring is either broken or possibly just weaken to a point that it doesn't properly close when cold. Also, if there is a lot of carbon build up on the valve stem this could also cause the valve to stick.