Make sure the trhottle housing is celan. On older 2.4 motronic cars this would cause a code injectors running lean/rich at idle. Cleaning the throttle housing would fix this. The 960 has 3.4 motronic I beleive, and it does seem to be a related (i.e. fuel injectors) code. What happens is the throttle body is so dirty it restricts the air flow at idle and then when it opens there is a huge air flow increase, very rapidly, this causes a lean then rich condition causing the computer to think an injector is bad. I would check the throttle body and clean it out thoroughly with some throttle body cleaner, this was part of the 30 000 mile service but it wasn't done at all dealers or by all mechanics, sometimes only when you complained about a stumble or miss when starting. Try this first and hopefully it will clear it up.