Would a pre turbo exhaust leak affect idle vacuum?

[jabinya]

I have noticed my idle vaccum dropping of the past couple of months. Did a compression check and it was within specs. Also did a boost leak test and found no leaks. After inspecting my exhaust manifold I found a crack between runners #3 and #4, top and bottom. The crack is aboubt a inch long but the sides doesn't look like it has seperated apart.

Hence my question; Would a pre turbo exhaust leak affect idle vacuum?

I have a auto trans and I also noticed when I move the gear selector from park to drive the vacuum drops another 2in. I suppose that is because of the load?

 

[DanThMan1983]

I dont believe an exhaust leak would effect vac

 

[VanIsleDSM]

what is your vac on idle? and yeah it'll drop from the load.

 

[DSMunknown]

An interesting question... I would also like to know how this would affect idling.



EDIT: If you need a fix to stop the leak, here is a recent thread that gives one possibility:
http://dsmtuners.com/forums/showthread.php?t=243756

 

[1997hciv]

Bringing this old thread back to life. I have an exhaust leak from the manifold to block gasket which causes bad boosting but I was also wonderig if it would effect my vacuum which is now 16 in.hg at idle. I have a new copper gasket which will be going on when I find the time but I also wanted to know if there could be something else that I dont know about. Thanks

 

[Burnett03]

It's possible because pre 02 leaks could cause the car to run rich.