Jaguar S Type MAP Sensor Causing Poor Performance & MPG

Had similar symptoms with a 2003 Jaguar X Type 3.0L. The sluggish performance and poor throttle response turned out to be a combination of vacuum leaks and a failing MAP sensor. The manifold pressure readings were irregular, causing the engine control unit to supply incorrect fuel mixtures. The vacuum leak was found at the intake manifold gasket, which had deteriorated. When testing manifold sensor readings, they were well outside normal parameters. The engine performance issues were serious enough to potentially cause long-term damage if left unaddressed. The repair involved: testing manifold sensor voltage outputs, Smoke testing to locate vacuum leaks, Replacing the MAP sensor, Installing new intake manifold gaskets, Clearing engine codes, Running diagnostics to confirm proper readings The automotive sensor replacement alone would not have solved the problem. The combined vacuum leak and faulty MAP sensor were causing the excessive fuel consumption and poor acceleration you described. These symptoms typically worsen over time and can lead to more severe engine performance issues if not addressed. Would recommend having both the vacuum system and manifold pressure sensor checked by a qualified technician rather than replacing parts individually.

Thanks for sharing your experience with the X Type MAP sensor issue. Glad you got it sorted out. My S Type developed similar symptoms about 8 months ago, poor throttle response and high fuel consumption. After getting it diagnosed, the MAP sensor and intake manifold gaskets needed replacement. The engine performance improved dramatically after fixing both issues. Just curious, what did the complete repair end up costing you? And has everything been running smoothly since the automotive sensor replacement? No other vacuum leaks or engine performance problems popping up?

The total repair came to 235€ for fixing the large vacuum leakage and replacing the faulty manifold pressure sensor. Since having the work done, the engine performance has been perfect with no additional issues. The fuel consumption returned to normal levels and throttle response is crisp again. The mechanic did a thorough job testing the intake manifold and MAP sensor readings after the repair. They also performed a complete system check to ensure there were no other vacuum leaks that could cause problems down the road. The investment was worth it since the car has been running reliably for months now. The sluggish performance and rough idle completely disappeared once they addressed both the vacuum leak and pressure sensor issues. No check engine lights or other warning indicators have returned. Based on the improved performance, I would say having both problems fixed together was the right approach rather than just replacing the MAP sensor alone.

I finally got the repairs done at a trusted mechanic after dealing with the sluggish performance for too long. The total bill came to 410€ which included replacing both the manifold pressure sensor and fixing the vacuum leaks they found. The difference in engine performance is incredible. The car responds instantly when I press the gas now, and fuel consumption has dropped back to normal levels. Having both issues fixed together definitely made sense, the mechanic showed me how the old pressure sensor was giving incorrect readings and the vacuum leaks were making everything worse. The repair process took about 4 hours total while they tested all the automotive sensors and sealed up the vacuum system properly. Three months later and everything is still running perfectly, no check engine lights or performance issues. Definitely worth the investment to have it done right rather than trying cheaper partial fixes that might not have solved the whole problem.