Did you see how Pep Guardiola went last season? He lost momentum to get his team into the Champions League places, but slowly Pep Guardiola managed to turn things around and eventually qualified for the Champions League. The title race might not be easy for Pep Guardiola this season, but I'm sure he's capable of putting pressure on both Liverpool and Arsenal.
This isn't a major issue, as every team will eventually face a Premier League match, whether they face a stronger team or not at the start of the season. I think the overall picture of which teams will compete for the title will be clear after the second half of the season, as it's still too early to judge those chances, although Liverpool may be the favorite.
I would say you are right. I think he has the chance to be third place this season too, and he will figure out what is wrong and will end up getting the best out of his team. But, I also think Liverpool is far above everyone else, and they are going to be the title winners this season. The trouble right now for City is that they do not look good, but the good news is that it has been only three games and they can do better.
This means that they have time to get better and Pep will figure out a way to do that. He could be the best manager we have right now in the world, to me Sir Alex Ferguson is the greatest ever to do it, but Pep is the best we have now and not far off from SAF neither, so it could happen. If there is anyone in the world that can fix this team, it's pep.