03 S-Type vacuum leak

[godelbor]

Greetings all. My S-Type has a P0174 & P0171 fault code, it stalls at traffic lights, RPM's surge intermittently, and the heater does not come on. I found it was a vacuum problem because I could hear a slight hissing sound near the firewall but what made it obvious is I disconnected an elbow hose, vacuum present and plugged it. Now problem has cleared up, heater comes on and car idles just fine. The check engine light goes off now occasionally. Feeling my way, this elbow plugs into a junction and best I can tell, the other side of this assembly is a metal tubing (injector rail?) going into the intake manifold. The vacuum diagram on my car is somewhat confusing me; the lines do not appear to be physically laid out as drawn but I am guessing I have disconnected the injector pressure sensor which may be another term for a fuel pressure regulator. I’m not a mechanic but mechanically inclined. Having research a bit, I have found that my vacuum leak could be the manifold gaskets, injector orings or something else like the fuel regulator IF this is indeed what I have disconnected. I have seen photos of the regulator and must say it does not appear that was what my hose was connected to. If I sound confused it is because I am lol. I will be troubleshooting some more in the next few days, perhaps use some tubing to pin point the leak by sound. The assembly I disconnected the vacuum line from feels more like a coupler, not an active device like a regulator; it’s a tight squeeze but am hoping to expose more of this area to get a better look. One thing is for sure; my problem is forward from this junction. I took pictures of this area but I guess they cannot be posted here. Can anyone shine some light on my problem? Thanks in advance.

[godelbor]

Update: I have discovered that the leak is on the bottom end of the metal piping where I have disconnected the vacuum line. It has another rubber hose which connects to the bottom; I guess this is what is commonly called the bottom elbow. My new question is what are the part numbers of the top elbow adapter (I damaged this removing it) & bottom rubber elbow. To be clear, the actual top elbow is good but it is coupled to a rubber adapter which enlarges so connected to the metal tubing is possible. If it helps any, the top elbow is connected to a long plastic like vacuum hose with p/n XR8E-6758-BG (Actually WERS #,see http://www.jaguarforums.com/forum/s-type-s-type-r-supercharged-v8-15/vvt-part-number-59166/). I suppose I could come up with a suitable substitute for these rubber connections so a more important question is what do I have to remove to gain access to the bottom elbow? Looks like I may have to remove the intake manifold but please advise as to minimal disassembly to replace this or is it worth having the dealer handle this? Thanks.

[godelbor]

Also forgot to mention, check engine light has not returned since I plugged the hose/

[Neil]

Did you remove the intake manifold to get access to it? As far as I remember the last time I managed to get it done without fully removing intake manifold.... glad to hear all is OK

[godelbor]

Neil,
Thanks for replying. I have not removed the intake manifold and have not yet repaired my problem; I still have the vacuum hose intentionally plugged to get by. Not sure how to access it;  I had to lay flat on my belly on top of the engine so as to get my arm in and around in a U turn position just to find it. I cannot see it in any angle but finally did place my hand on it. I suppose there is always the possibility what I am referring to is not the lower elbow. Wish I could post pics.