Rough-running Infiniti EX: Bad Sensor or Bigger Issue?

Hey there, I had the exact same issue with my 2016 Infiniti QX50 diesel last winter at 45K km. The symptoms matched perfectly rough running, power loss, jerking during acceleration, and increased fuel consumption. The diagnostic confirmed it was indeed the intake manifold pressure sensor wiring harness that had deteriorated. Took it to the Infiniti dealership since this was a fairly complex electrical issue. The wiring harness had several corroded connections and one completely broken wire. They had to replace the entire harness assembly and recalibrate the sensor. The job took about 4 hours. While it wasn't the most serious issue I've faced, leaving it unfixed could've led to further engine damage. The sensor sends crucial data to the ECU about air pressure and mass flow, so when it's faulty, the engine runs with incorrect fuel mixture. I'd strongly suggest going to the dealership for this one. The wiring requires specific knowledge of the Infiniti electrical system, and they have the right diagnostic tools to ensure everything's properly calibrated afterward. Hope this helps.

Thanks for sharing your experience! That's really helpful as it sounds exactly like what I'm dealing with. Just curious do you remember roughly how much the repair set you back at the dealership? Also, has everything been running smoothly since the fix, or have you noticed any other issues pop up?

Hey again! Just wanted to update you on my repair costs I paid 95€ to get the intake manifold pressure sensor wiring harness sorted out. Since getting it fixed, my QX50's been running like a dream! The jerking and power issues are completely gone, and fuel consumption is back to normal. Honestly, I'm so relieved I got it taken care of at the dealership. I know I mentioned it was about 4 hours of work in my previous post, but trust me, it was worth every penny to have it done right. Haven't had a single problem since the repair, and it's been over a year now. The engine runs super smooth, no more check engine light, and the acceleration is crisp again. Really was just the wiring harness being faulty once they replaced and recalibrated everything, all those annoying symptoms disappeared completely. Sometimes it's worth paying a bit more to get it done properly the first time, you know what I mean? Let me know if you need any other info about the repair. Happy to share more details from my experience!

Thanks a lot for the detailed follow-up! Just got back from the dealer today actually. You were spot on it was the wiring harness causing all the trouble. Ended up paying a bit more (120€) since they had to order the part from another city, but I'm not complaining. The whole experience was way better than with my previous mechanic. They showed me the corroded wires and explained everything clearly. Car's running perfectly now no more jerking or power issues, and my fuel consumption is back to normal. Such a relief! It's funny how we had such similar issues. Really glad I asked here before trying another unusual mechanic. Saved me from potentially getting ripped off again. Thanks again for steering me in the right direction with the dealership suggestion. Sometimes paying a bit extra for proper service is totally worth it! Best decision I've made for my car in a while. Now I can finally enjoy driving again without worrying about every little noise or problem!