Infiniti EX Diesel: Serious Power Loss & Engine Troubles

Hey there! I've got some experience with cars (I'd say medium level done basic repairs but no expert). Had a super similar issue with my 2013 Infiniti FX Diesel last year. Same symptoms rough idle, jerking, and that annoying check engine light. Turned out it was indeed the intake manifold control switch that went bad. Took it to my regular workshop, and they diagnosed it pretty quickly. Cost me about 465€ for the whole fix parts and labor included. Mine was actually making this weird hissing sound too, just like yours. The mechanic showed me how the intake manifold control wasn't responding properly, which was causing all those symptoms. What's your current mileage and maintenance history? Also, are you getting any specific error codes? This info would help me share more relevant details from my experience.

Thanks for sharing your experience! My mileage is at 238431 KM, and I just had my last service two months ago. That price doesn't sound too bad if it fixes all these issues. I haven't pulled the error codes yet, but I'll definitely get that done tomorrow. Did your car also feel really sluggish when accelerating? Mine feels like it's lost quite a bit of power, especially when I'm trying to overtake on the highway. I'm actually relieved to hear someone had similar symptoms and got it fixed without major drama. Might take it to the workshop you mentioned if it's in my area would you mind sharing which one you used?

Yeah! Glad to help out again. My FX was definitely sluggish during acceleration exactly like you're describing. It was super frustrating, especially on highways. I remember trying to pass someone and the car just wouldn't respond properly. It felt like it was only giving me maybe 60-70% of its normal power. Your mileage is pretty close to what mine was when I had the issue (I was around 245,000 KM). Actually, the mechanic told me this is a fairly common problem for our Infinitis around this mileage point. I took mine to AutoTech Solutions in Munich (that's where I'm based), but honestly, any decent workshop with experience in Infinitis should be able to handle this. Just make sure they've dealt with intake manifold issues before it's not super complicated, but you want someone who knows what they're doing. One thing I forgot to mention in my first reply after they fixed it, it took about 50-100 km of driving for the engine to fully adapt to the new settings. So don't worry if it doesn't feel perfect immediately after the repair. Keep me posted on those error codes when you get them. It'll be interesting to see if they match what I had (mine showed P2008 and P2009).

Thanks so much for all the detailed info! Unfortunately, I'm not in Munich (I'm in Manchester), but I'll definitely look for a workshop here that specializes in Infinitis. It's really helpful to know about that adaptation period after the repair I would've probably freaked out if the car wasn't running perfectly right away! Just got back from getting the codes read, and guess what? Same exact codes as yours P2008 and P2009! Really confirms what we're thinking about the intake manifold. I'm actually feeling much more confident about getting this fixed now, especially knowing it's a common issue at this mileage. Thanks again for all your help you've saved me a lot of worry and probably some money too by helping me narrow down the problem. I'll book it in for repairs next week and hopefully get my car back to its normal self!