Not being a Saab expert myself but having had a Lambda problem recently ill try to help,i assume you dissconected the battery after fitting the lambda to reset the fault code,if you have and its still on it could be the new lambda causing the problem still.Was it a genuine part or o/e copy?as the Saab's are very sensetive to Lambda resistance and tend to not like universal sensors.It could also be a faulty map sensor as i believe that can give the same flash code.I believe resistance on the lambda should be 3-4 ohms,outside that range and it wont run properly.