above is a scan of a map sensor against a injector, the top line is the MAP sensor and the bottom is the injector. At idle the MAP line will stay constant as the pressure will stay the same and the injector pattern will stay the same and at regular intervals. if you rev the engine the MAP sensor would raise as the pressure increases and the injector patterns would be closer together and the bottom line where the injector is being earthed will be longer to inject more fuel.
