There are 15 languages spoken in China and that is just the major ones. They are each as different from one another as English is from German or French or Greek of Latin. China is an old civilisation, it spawned Genghis Khan who fought his way across all of Asia and Russia to Vienna only stopping because he over extended himself. It has the largest population of any country in the world and for Americans who think that China needs democracy reinstated it never has experienced democracy in its long history. Democracy is as foreign to China as the cheese would be to a martian. The one thing China has a lot of besides people is patience.
After the death of Mao Zedong and the overthrow of the Gang of Four within the PRC a momentous change happened. After he was rehabilitated and returned to the Politburo, Deng Xao Peng reformed the economy, the result of which we see the today. An inspired move because it has bought great wealth and change to China. However the reforms were only economic, not political and given that the PRC was then, and still is, a Marxist Leninist state, Deng would have signed his own death warrant by advocating political change. He didn't want political change just economic change because he knew that if there was no change to the Maoist economics, the state would wither and die along with millions of its citizens. All of the veterans of the Long March may have departed this world, but their political ideology, government structures and methodologies are still currently in force. The Politburo do not tolerate change easily and they have far less tolerance of anything that threatens their grip on the helm of state - their grip on power.
Now in the 21st Century the PRC has a number of issues that it has to face. A burgeoning young wealthy, traveled and educated middle class who are tech savvy and want more than just the standard Party line. The PRC also wants to replace the US $ as a major trading currency, but before it can do that it has to float its' currency. Politically that will be unacceptable to the Politburo. Whilst it would make economic sense, it would be political suicide and probably personally fatal for them to agree to it. Rival factions within the Central Committee would see it as giving control of their treasure and national sovereignty to foreign devils. Remember that the Politburo and the Party do not tolerate departure from the party line and failure.
Already alluded to by DarthAmerica are the workers wanting a greater share of the profits. Because of the economic reforms there has been a marked internal population migration from rural areas to rapidly increasing urban spaces. This migration exacerbates pressures on existing infrastructures, social and political systems. Resources are having to be diverted from rural areas to support the burgeoning urban areas. Rural areas still have a very low GDP with a real possibility of most rural populations living below the poverty line. So there exists two sets of discontented sections, although highly disparate, of the population. How the Politburo deals with this set of problems will be of great interest considering the constrictive dialectic they work within.
Another cause for concern is the PLA. Unique amongst all of the worlds major militaries it has an extensive economic empire as well as being funded by the central government. By convention the Secretary of the Communist Party is also the Chairman of the Central Military Commission (I am doing this from memory so might not have the terminology right), Chairman of the Politburo and Head of State. So in theory the PLA should answer to the Politburo (and by default Party) through both the Central Military Commission and the Political Officers within the PLA. But the trappings and baubles that are gathered by having access to wealth, generated by ones own economic empire without the oversight of ones masters, must surely tempt even the most zealous and politically reliable officers and political cadres within the PLA.
If you are going to discuss a US - Chinese cold war then one should understand a bit about China and not look at it through the lens of a western mind set. If any have been to a military War College or similar they should have read the Sun Tzu Ping Fa, very old but just as relevant today. Don't expect China to act the same way a western nation would to any given set of circumstances.