You need an oscilliscope to measure those readings, you'll never pick them up on a multimeter.

@Captiva, testing the sensors like you did doesn't always test the wiring properly.

For example my mates car had an intermittant fault that wouldn't show up on the meters, but did when the car ran. I can only assume the engine vibrations were causing the poor contact?

Just a thought, have you checked the vacuum tubing to the map sensor for holes?