I recommend creating a new TFS permissions group via the "Group Membership" dialog under either "Team Project Collections" or "Application Tier" in the Administration Console, for a collection-specific or server-wide group, respectively.

With or without a dedicated group, to deny all source control access, open up Source Control Explorer in VS, right click the root folder, then select "Advanced > Security...". Click Add and select either the group you created above or the individual user if you did not create a group. You should then be able to simply deny whichever permissions you want, here.

To explicitly grant permissions for Web Access for a given project, go to the web access administration panel, select the project to which you wish to grant access, then select "Manage project security and group membership". Select the "areas" tab, then right click the root area and select "Security" from the context menu. Click Add and select the group or individual, as before, then set the appropriate permissions on the right.

Let me know if you need any more clarification.

how to add project manager to TFS 2012
I have a 1993 Mazda 323 estate (GLXI 1.6l petrol).
It's not been terribly reliable and has suffered from inconsistent idle - sometimes idling fast (~1500 rpm) and sometimes erratically and sometimes cutting out when stopped at lights.
The last mechanic I took it to said it was probably a problem with the air mass meter - he did some 'bodges' on it to try and get it working but the car has still failed to start on one occasion. It seems to start and drive ok at the moment, but I'm not sure how much longer it will continue to do so!

Is this likely a problem with the air mass meter or is it likely to be something else?

Also, does anyone know where I could get hold of a new one? (I'm based in the UK) 
