If I deciphered your post correctly, you are currently taking 4mg's of suboxone a day.
If you want to quit, you need to drop your dose to about 2 mg's immediately. You should feel no withdrawal when doing this, and if for some reason you do, simply take tiny doses of suboxone until you feel better again. But, you should be able to get down to 2 mg's very quickly.
Then, start lowering your dose every other day or so by about 0.2-0.5mg's. Do this at a comfortable rate(you may have to do it slower than I described but most people would be extremely suprised by how little suboxone they can get by on even if they were at a higher dose, suboxone IS NOT like other drugs). Do this until you reach comfortable dose of about 0.2-0.5mg's.
Then, stay at this small dose for atleast 3 weeks, if not more. Then, once you have completely stabilized on this dose, you should be able to drop off there with little to no pain whatsoever. I take up to three 0.5mg doses every single day and I can stop taking suboxone whenever I want, for however long I want. It all has to do with the tiny dose, and being able to maintain on it for a long period of time. So, yes, this will take some time, but unfortunately thats what you got yourself into when you got on suboxone.
*Side note, at doses lower than 1-2mg's you should atually feel euphoria and energy boosts from the suboxone. This all has to do with bupe metabolite norbupernorphine that is a full agonist and can get you high and euphoric. You can use the search function on BL to find out all the information about that that you want. It has been extensively talked about.
Good luck!!