Mercedes C Klasse Engine Performance Issue

My 2000 Mercedes C Klasse with a gasoline engine is acting up. It has 77923 km. The check engine light is on, performance is down, response is sluggish, and fuel consumption seems high. I'm wondering if it's the manifold pressure sensor. I suspect a vacuum leak is causing the MAP sensor to report bad data. Anyone seen this before?

4 comment(s)

I had a similar issue with my C Klasse a while back. Your symptoms sound really familiar. The engine just wasn't running right, and MPG was terrible. Have you checked for any obvious cracks or loose hoses around the intake manifold? It's worth a quick look before digging deeper. The pressure sensor itself might also be the problem, but a vacuum leak is definitely possible.

Thanks! I looked at the hoses, but I didn't see any obvious cracks. Is there a better way to check for a vacuum leak? Did changing the sensor fix your engine, or was there something else?

For me, replacing the pressure sensor worked. You could try smoke testing for vacuum leaks, but it can be tricky without the right gear. Honestly, with those symptoms and the car's age, I'd suggest a workshop. They can properly diagnose it, which could save you time and hassle. It could just be the sensor going bad.

Thanks for the advice. I took it to a local shop. Turns out the MAP sensor was bad, probably from a small vacuum leak that was hard to find. They replaced the sensor and fixed the leak. The total cost was 235€. Engine performance is back to normal. I appreciate the help!

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