2. There is an election in the House to choose a replacement for Speaker of the House.
3. Conservatives believe that Boehner was unable to deliver conservative policies despite huge electoral gains. Boehner wanted to avoid extreme tactics. Conservatives wanted more than what Boehner would provide for them.
4. The coming government funding showdown revolves around Planned Parenthood. Federal money is going to Planned Parenthood to reimburse them for health-care services, but Planned Parenthood may use that money for other things. This angers many Republicans, because they do not like that the government is indirectly paying for abortions.
5. The Tea Party has teamed up with some Republican conservatives, so they can can promote a Republican to lead the House.
6. Boehner believes that House Republicans already accomplished what they could realistically achieve. They would not push the boundaries that the conservatives desperately wanted to push.
7. Kevin McCarthy, a Californian Republican, is the most likely choice to replace Boehner. I think he may not do a great job, because he is stuck in the same situation as Boehner. He has similar views to Boehner, so the conservatives will be unhappy with him.