I would count to 10 very slowly before I sell the car; this could all be due to a bad Engine Management Relay (including the ETM-related symptoms). Could you list the exact DTC codes that you pulled? (Sorry, I've never used Mitchell)
2002 S60 2.4 non-turbo - lovely!
1987 340 DL (with the 4-cyl N/A Renault Diesel engine, 5-speed manual, RWD) - sold (I wish I did not have to...)
Definition for Stupidity: Doing the same thing over and over and expecting different results...