Just bought 1992 960. It's a one owner, immaculate condition beauty. The only problem is that it will only fire on 4 cylinders. I can drive it fine, it won't stall and the tranny is strong. It idles at a steady 600 to 650 rpm, but of course, very rough. I know that is a little low, but assume it is because two cylinders are not firing.

I am hoping that to knowledgable volvo people, this will be an easy fix. The cylinders in question are the second from the front and second from the rear. Sorry I don't know what numbers they are. I think the front most and rear most cylinders fire together and the middle two fire together. With this understanding, I believe the two in question fire together, so i'm hoping one of the guru's of this fantastic site can tell me what simple, easy to fix mechanism controls the firing of these two cylinders.

After reading through the site,I have attempted these fixes and checks.
-switched power packs located on the intake manifold (front and rear)
-switched injector relays located above wheel well next to ecu check light.
offending cylinders did not change in either case (darn it I thought one of them would work)
-cheched for vacuum leaks (none found)
-replaced iacv
-checked for spark (good there)
-switched around injectors (no change)
-checked for injector voltage (good there)

This problem is suckin' the life right out of me. Any help would be much appreciated.