Hey guys, so the jag has been starting rough until warming up. I've been getting the cruise not available and the bucking to go with it, but also the break pedal has been getting hard when it happens which leads me to believe it's the brake line booster. I knew from searching on here it's likely a vacuum leak of some sort.

Today My car wouldn't start at all. Combination of - 2 temps, vacuum line and the battery draining from me turning it over so much.

Does anyone have a picture of their engine bay they could use Microsoft paint or something to circle where the most common vacuum leak hose culprits are for me to make it easier to find and diagnose them? I will be outside in freezing temps doing this so any help to make it quicker would be huge. Thank you!

 

I have the purge line go on me a few weeks ago.

Here is a picture of my engine bay before the fix where I highlighted the brake booster and purge line for you.

In regards to diagnosing, as soon as I opened up the hood, I could hear the leak and it took me right to my purge line.

I wouldn't call myself an expert by any means, so check those two out and wait for some of the experts to chime in. The bucking is most likely the car going into limp mode based on the leak. Mine has electrical tape holding the two pieces together. I received the line over the holiday and will replace it sometime in the next few weeks, as I am in the same situation as you with the below 0 temperatures.

 

Five, if you look at the picture that 91 posted (the one of the whole engine bay). The 2 points that he circles are good ones (granted, the back circle normally is the little black/gray "football" in the center goes bad).

Next, if you look on the air box where it says "Jaguar", see the ribbed hose above the "U and A" in Jaguar? That hose is known for developing a split in the hose on the underside (this is especially true if the hose is smooth unlike the ribbed hose shown here).

Finally, you can see the silver intake on top of the engine. If you look on the left end of that (facing the strut tower), you will see two 4" black plastic circles. Those are the IMT (Intake manifold tuning) valves. There are o-rings under those plates that are known for developing leaks and leading to vacuum issues.

 

Thank you, very, very much guys for taking the time to help me. I'll be sure to check those spots first before I send it off to a shop to waste my money haha. I'll update as soon as I figure it out.