Throttle body vacuum lines

I finally got the courage to see what’s going on underneath the intake. I found this post in Rennlist forums.rennlist.com/rennforums/928-forum...as-disconnected.html
MY87 has 4 vacuum ports top and bottom of throttle housing. One of the bottom vacuum lines has a plug. Also one of the T distributing piece also has a plug. Is this correct?
PETS show 4 goes into some where but the one points to the firewall but I didn’t any thing missing. Where should the fourth one plug into?
All, Thanks in advance

Attached files [img]media/attachments/1383=129-Bottom Vacuum.JPG[/img] [img]media/attachments/1383=130-pet.jpg[/img] [img]media/attachments/1383=131-Top Vacuum.JPG[/img] [img]media/attachments/1383=132-Vacuum T.JPG[/img]

Sometimes you won't need that extra connector hole. I've seen them plugged on both Auto cars and on 5 speed ones. Usually it is a crew pushed in there.

If most of your emission stuff has been removed, there will be a couple more holes plugged also.

It looks to me like it is time for an intake refresh so you can replace all of those old connectors with new ones. I end up using, on the auto cars, 2 4-way connectors and 2 3-way connectors in place of those 5 and 7 way ones. It's all old stuff, get new and don't worry about it for years.

SeanR;1394 wrote: Sometimes you won't need that extra connector hole. I've seen them plugged on both Auto cars and on 5 speed ones. Usually it is a crew pushed in there.

Sean Thanks
It's been 8 years since I had someone do the intake refresh. The rubbers still look good. Only thing I have removed is the two exhaust gas test ports at the back of the engine. The smog pump devices are still intact and working. I'm in here fishing for some vacuum lines that might have leak or got pull out.
I'm having irregular idle issues when at idle in City driving. I don’t have issues when driving in the freeway. I drove home from Kentucky to Chicago from a fellow 928 and no issue what so ever. While visiting my buddy in Kentucky he did a vacuum leak test and mentioned that I might have a vacuum line that either broken or got pulled. Since we replaced motor mounts, oil pan gasket and remove the exhaust gas test ports.

Any ideas what the issue might be?

Sounds like a minor vacuum leak to me, although it could be a number of other things, like TPS, ISV, fuel dampener leaks....the list is long.

Vacuum leaks can be very hard to isolate and it can try your patience. Sometimes you can hear them and sometimes you can't. The best way to chase them down, in my opinion, is with starting fluid. Just remember to use caution when chasing leaks with starting fluid. Don't spray down ignition components, for instance. But, if you have vacuum leaks, starting fluid is the one of the surest ways to tell.