So I was getting a little hesitation and the car was running rough, with the help of everyone here, I checked the hoses and found that the brake booster hose that goes into the top of the engine, can be just pulled out and doesn't seem to be held by the plastic coupling. Can I order just the coupling?

 

I believe you can only get it with the brass fitting (probably not needed, and can be thrown away). The plastic clip and o-ring can be inserted. THe cheapest I've found is here: Jaguar Brake Booster Hose Connector Kit C2S15816 | eBay

 

Thanks for your help, I just ordered it