Laguna MAP Sensor Fault

I had almost the exact same thing happen on my Laguna! Check engine light, sluggish performance, the works. I didn't chase vacuum leaks for too long before my mechanic suggested the MAP sensor might be the culprit. Seriously, consider checking the sensor before ripping your hair out looking for phantom vacuum leaks. Sounds like you've got a good handle on the symptoms though - any chance you've hooked up an OBD2 scanner yet?

Thanks for the quick reply! Yeah, I did hook up an OBD2 scanner. It threw a code related to the manifold pressure, which is why I'm leaning towards the MAP sensor. Was the sensor replacement straightforward on your Laguna? Did you notice any other weird symptoms besides the ones we both mentioned?

Okay, a MAP sensor code definitely points in that direction. On my Laguna it was a pretty simple swap, but honestly, given your symptoms (and the code), I'd strongly recommend getting it properly diagnosed at a workshop. Vacuum leaks can be tricky to pinpoint, and a faulty MAP sensor can sometimes be a symptom of a larger issue rather than the root cause itself. Best to be safe and avoid potentially causing further damage. If it IS just the MAP sensor it'll be a quick fix. I ended up paying 235€ for the entire repair.

Thanks a lot for the advice! I took your suggestion and brought it to my local shop. Turns out the MAP sensor was indeed faulty and was causing a large vacuum leak, just as we suspected! Replaced the sensor, and now my Laguna is running like a champ again! You saved me a lot of time and headache!