Kind of a vague problem description. Can you be more detailed? Is it possible the accelerator linkage is binding or staying partially applied?

The OVP will be the least of your issues, if it has intermittent problems, you'll have plenty of symptoms.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]