The OVP is the source of hot start problems and can cause stalling while driving, but is not related to rough idle problems...unless, as mentioned earlier, the fuse is blown.
Check ignition components, fuel pressure regulator, and injector seals...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car