Sometimes engine system service required comes up on the dashboard. And there is loss of power between 1500 to 2000 rpm. Do you know what it might be.

Hello, no guesses to be made, but the warning light that is coming on will help you with clues to direct your attention to. Using a proper diagnostic tool, trouble codes can be pulled to find out what is being seen by the engine's processor and setting the warning light to come on. Often times, this is related to the performance problem you are having. It's a great starting point to your testing and diagnosis.