Defender's Symptoms Point to Major Intake Manifold Issue

Hey there! I had nearly identical issues with my 2005 Land Rover Discovery 3 diesel last month. The symptoms matched yours exactly, rough idle, power loss, and that distinctive hissing noise. Turned out my intake hose had several small cracks and one major split near the turbo connection. At the garage, they found that the rubber intake hose had degraded from heat exposure over time. It was causing a significant air leak, messing with the air-fuel mixture. They had to replace the entire intake hose assembly and a few connecting clamps. Not a super serious issue in terms of engine damage, but definitely something that needs fixing ASAP since it affects engine performance and can cause other problems if left unchecked. The job took about 2 hours. The most time-consuming part was accessing the hose since it's tucked behind other components. If your symptoms match what I experienced, I'd definitely get it checked out soon, these issues don't fix themselves and typically get worse. Hope this helps!

Thanks for sharing your experience! That's exactly what I was dealing with on my Defender. I finally got it fixed last week, and it's running like a dream now. The mechanic also found the cracked intake hose, you were spot on with that diagnosis. Just curious, do you remember roughly how much you ended up paying for the repair? And has everything been running smoothly since, or did you notice any other issues pop up? These old Defenders can be pretty temperamental sometimes!

Hey again! Glad to hear you got your Defender sorted out! Yeah, after I got my Discovery fixed, it's been running like a champ. The whole repair set me back 100€, pretty reasonable considering how much of a headache those symptoms were causing. The mechanic replaced the cracked intake hose and double-checked all the connections, and I haven't had a single issue since. You know how these old Land Rovers can be, they love to keep us on our toes! But honestly, once that intake leak was fixed, all those annoying symptoms disappeared completely. No more hissing, no more rough idle, and the engine's got its power back. It's amazing what a difference fixing one leaky hose can make! Just keep an eye on those rubber components, they tend to wear out over time with all that heat exposure. But at least now you know what to look out for if those symptoms ever pop up again. Happy driving!

Thanks for all that info! Yeah, my repair experience was pretty similar. Finally got down to fixing it last week, and you're right, it's like driving a completely different car now! My bill came to about $150 total, including labor. The mechanic really knew his stuff, found the cracked hose right away and even showed me where it had split. The funny part was watching them dig around the engine bay trying to reach that hose! Took a bit of creative maneuvering, but they got it done in about two hours. No more shaking, no weird noises, and the engine's running super smooth. Check engine light's finally off too, which is a massive relief. Definitely learned my lesson about getting these things checked out sooner rather than later. I wasted way too much time with that first mechanic who couldn't figure it out. But hey, at least now I know exactly what that hissing sound means if it ever happens again! Time to enjoy my properly running Defender, fingers crossed it stays this way for a while!