idle problem

["Jonas P" <Delorean3543@xxxx>]

This problem usually only happens on cold starts. After starting my 
81 D the engine races up and down. At an idle in park it sounds like 
someone 
is pushing up and down on the gas peddel. When you put it in drive it 
still happens but not as bad. Sometimes I can rev the motor to around 
4000 RPM's a few times and it quits. After the motor warms up a bit 
it stops. I know for sure I have a vacaum leak, John Harvey is 
putting 
together a silicone hose set to replace my old ones. Would a vacaum 
leak cause this type of problem? If not, Anyone know what would cause 
this?
Thanks
Jonas 3543