The problem is with a 1994 CDE. When accelerating fairly hard in most gears the engine will miss badly a between 3,200rpm and 4,500rpm If the acceleration is gradual this does not appear to happen.

Check all wiring and connectors (clean) particularly earth leads for the DI unit, the red thing above the spark plugs. Inspect DI unit for signs of oil leaking out of one of the 'coils'. If it is a problem with the DI unit a new cost £165 for Saab. Best to try swapping with one from another car that is running OK to check. Could try asking local Saab dealer if you can borrow one.

I changed the plugs as they were quite badly erroded, but this did not make any difference. After few days of running the characteristic of the fault changed slightly, and the went away completely. It was suggested to me that the engine management system may have re-mapped itself to cope with the bad plugs, and took somtime to get use to the new ones, could this be considered likley?

Found out what the problem was. the waste gate actuator had corroded to the bellcrank of the waste gate not allowing to operate resulting in over boosting