Rough Running Compass: MAP Sensor Issues Explained

I had a similar issue with my 2017 Jeep Cherokee. With some experience working on cars, I can tell you this sounds very familiar. The check engine light and rough running were exactly my symptoms. After checking the air intake system myself, I finally took it to a workshop. They found the hose connection from the pump to valve was defective, causing inconsistent manifold pressure and affecting the air supply to the engine. The repair involved replacing the faulty connection and testing the throttle body function. Total cost was 175 Euro including parts and labor. The whole job took about 2 hours. Before suggesting more specific solutions, could you share: Current mileage on your Compass? Any recent maintenance work done? Does the rough running get worse when the engine is warm or cold? Have you scanned for error codes? These details would help determine if your issue matches what I experienced. The symptoms you describe definitely point toward an air delivery problem, but there could be multiple causes.

Thanks for checking my case. My Compass has 118225KM and got its last major service 4 months ago. The engine stalling happens mostly when the engine is warm, and it gets worse during humid weather. The throttle body feels unresponsive, especially during initial acceleration. I did scan for codes using a basic OBD reader which showed P0171, indicating a possible vacuum leak or air supply issue. The idle problems are definitely more noticeable after the engine reaches operating temperature. The service history is clean with regular maintenance following the schedule. No major repairs were needed before this issue started appearing two weeks ago.

Thanks for providing those details. Given your P0171 code and symptoms matching my previous Cherokee issue, I'm now even more convinced we dealt with the same problem. The vacuum leak in my case also showed worse symptoms in humid conditions, and the idle problems were more pronounced when warm, exactly like yours. The P0171 code was the same one I got before finding the defective hose connection. After fixing my air valve system and the associated vacuum hoses, the engine performance returned to normal. The instability during warm idle completely disappeared, and the manifold pressure readings normalized. One additional detail from my repair: the shop found that the throttle body needed cleaning during the diagnostic process. This extra step added about 40 Euro to my original repair cost, but it helped resolve the unresponsive acceleration issue you're also experiencing. Since your symptoms are nearly identical and the diagnostic code matches, I strongly recommend having your intake system thoroughly checked, particularly the connections between the air valve and manifold. This should resolve your idle problems and restore proper engine performance.

Thank you for the detailed response. Your experience with the Cherokee is really helpful, especially since the symptoms match so closely with my Compass issue. The humid weather correlation and similar P0171 code definitely suggest we are dealing with the same type of vacuum leak problem. The price range you mentioned for the repair sounds reasonable, and 2 hours of labor time fits within my schedule. I will schedule an appointment with my shop and specifically ask them to inspect the air valve system and manifold pressure connections. The throttle body cleaning recommendation is also valuable since I am experiencing similar acceleration response issues. I feel much more confident now going into the repair with a clear understanding of the likely problem and expected costs. Will follow up on the forum after the fix to confirm if this resolved my engine stalling and rough idle problems for others who might face similar issues. The total repair estimate of around 215 Euro including the throttle body cleaning seems like a fair investment to restore proper air supply and engine performance.