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Map Sensor?

I’m looking at a 1999 Corvette with the LS1 engine. The seller says he’s had trouble with the “map sensor”. I’ve never heard of that, but the man says if he plugs it in the engine runs rough. He unplugs it and the engine runs fine. Any thoughts on this?

Several possibilities. How many miles one it. It may just need cleaning. Has the car been used without an air cleaner or maybe with a K&N oiled filter? Does that model and year have a CEL light? Is it on?

You might check to see if it has any error codes stored. Did the seller explain what he has done if anything other than to unplug it?

The real issue I would have with the car is not the MAP, but rather the owner who appears to believe that maintenance is something you only do after the damage is done.   I would be real careful about this car.

The Manifold Absolute Pressure sensor controls the fuel mixture and ignition timing. So yes, if the MAP sensor is faulty the engine can run rough.

If you’re planning on buying this vehicle, have the owner replace the MAP sensor before doing so.


MAF sensors can often be recovered by cleaning them. I don’t think that the same is true for MAP sensors.

MAF = Mass Air Flow, usually near the air filter.

MAP - Manifold Absolute Pressure, usually somewhere near or on the intake manifold.