Newbie

Hi all, I'm Mike I've recently bought a Laguna 2 1.9 dci sport tourer. She's nice to drive all though she does have a few problems, the main thing being the fault in fuel injection warning being on all the time. It will occasionally loose all power but if I turn the engine off then back on again she's fine. I've changed the egr valve. Just wondering if there's anything else I should be doing. Any help you kind people can give me would be gratefully appreciated. Regards Mike