Problems with Mercedes V8?

Does the McLaren Team has problems with the Mercedes V8 engine again? Kimi Raikkonen had to stop during free practice this afternoon, with what the team describes as an 'electrical problem'. Rumours say though, that Raikkonen suffured a problem with his engine. Reports are spread that after Raikkonen, also Montoya would have a malfunciton on his Mercedes V8. If this means that both drivers need a engine change isn't confirmed yet!