When I start my "96" 850 turbo, the engine cranks and sometimes will start right off, but, sometimes it cranks for almost a minute then it almost feels like there is too much compression and then like no compression at all, but doesn't start.
It then repeats the same feeling (but has short periods of what seems like air leaking and then stops, as if you quickly let air out of a balloon, but no engine crank) then after 4 or 5 tries it will again crank and may or may not start. This is a real strange one. I also just replaced the plugs a couple of months ago and it ran fine for two months. Any ideas greatly appreciated.