Have replaced the i.c.m,coil,spark plugs,spark wires,rotor,distributor cap due to misfires in all cylinders but still #4 cylinder is not burning all its mixture.done a cylinder drop test on it and no change at all in idleing.its getting spark at both ends but when I pull the spark plug out its still wet or soiled with gasoline.want to know what could be causing this?

The plug in cylinder #4 may be shorting out. I would remove the plug, lightly coat the porcelein and the end of the electrode with dielectric grease, and ensure the spring contact in the plug wire is squarely seated over the electrode. Also, I would only use the same plugs that came in the car. These are likely NGK plugs. Make sure they are properly gapped.

I would also coat the ends of the spark plug wires, where they go into the distributor cap, with dielectric grease.

Still having trouble getting #4 cylinder to burn off its mixture;replaced plugs,icm,coil,wires,cap n rotor,pcv valve,have used dielectric greased.im really confused,would a bad O2 sensor make that cylinder do that?since the primary O2 sensor controls the A/F mixture.

That could be a factor. Also, perform a compression test and a leak down test on the engine. You may want to follow the steps in the link below:

Determining the missing elements in misfires - Misfires occur when the combustion process is incomplete, so you need to find what's missing. - Motor Age - Automotive training, certification & parts