1996 Blazer 4.3 Cylinder 3 & 5 misfire
 

I have a very troublesome Blazer on my hands and could use some help. Its a 1996 blazer with the 4.3 code W motor, brought in running very poorly for a major tune up. After replacing the cap, rotor, wires, plugs, Spider(MFI), FPR, PCV & hose, and LIM gasket, all with AC Delco parts, it runs far better then before. Unfortunately it still is misfiring both cylinders 3 & 5 at idle, smooth while accelerating, compression and fuel tests are good. Strangely enough while idling if the PCV is pulled it will smooth out. Any suggestions of something I may have missed or should try? Sorry if I missed a post about this, I've been mucking about the forums for a few hours now and figured I should ask.

Thanks in Advance
Joe