sparki

hi all... i'm new here and have an 07 ybr.... fuel injected. everything going alright cept for this afternoon when the engine management light came on and now stays on. have checked pipes, connectors etc and all appears ok on the outset.... cept the idle won't stay constant... it'll drop and cut out. starts fine and i can hold the throttle to keep the revs up but it's only been doing this since the management light came on..... owners manual says take it to yamaha but that = £££ so if anyone has some ideas on what to look at / check first it would be appreciated... battery was flat last week but after a night on an optimate all was fine again.... no probs since besides this one... any ideas? cheers