Check injection/ ESP,ASR defective

Hello Renaulter, I have a problem with my Megane Phase 2 1.6.16v from 2003. And indeed the car starts to stutter after about 15 KM, as if a ignition coil is defective, and I get the error messages: Injection check/ ESP/ASR defective. From Renault I got an estimate over 280€, where they just want to change everything, injection, cable trees, control unit….. Does it seem to me that they don’t even know where the error lies, because first they had the ignition coil changed. Has someone had the same problem, or an experience in this kind. Error occurs only when the engine is warm. Thanks Fünner