Driving in a high gear at low speeds - a question

I have been reading more reviews about driving in a high gear at low speeds to achieve fuel economy. I have tried this since and can happily plod along at 30mph in 5th gear (manual) on a reasonably level road. The rpm is around 1000, how is possible that I can take my foot of the accelerator and the engine will continue to turn over and run at a near constant 30mph?

The mpg has been anywhere from 60+, also will this be potentially causing any engine damage? Much obliged to hear you thoughts.

Asked on 21 November 2012 by James

Answered by Honest John
Because that is the engine's idling speed.
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