Never at idle but at highway speed my car has had a nailing problem that I solved by re-torquing the DV holders. Also, tiny bubbles in the fuel lines can do it.

I also replaced the rubber line from the firewall to the fuel heater and that helped. I think it was sucking air somewhere along the line. Sometimes I get tired of chasing air leaks in that system.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250