Engine Performance problem
2000 Other Jaguar Models 6 cyl Two Wheel Drive Automatic 90000 miles

I have a 2000 s-type jaguar 3.0 v6,It has a idle misfire.no fault codes showing or recorded,no warning lights on or ever has been,on emision test shows runing weak on passenger side bank,garage said drawing air in,I so far have had all spark plugs replaced,coil packs checked all ok,inlet manifold gaskets replaced upper and lower,breather elbow pipes replaced,compressions tested all ok,but still misfire on idle,it seems to be all cylenders on that side because no matter which coil pack is taken off when engine runing it makes no differance to miss. I will donate when i get a reply that fixes the problem,as i have paid before for this on other sites with no real help in fixing it,just re-check whats been done?