CHENGDU, CHINA — With more than 100 very tall cranes on the skyline, this large metropolis in Sichuan Province looks vibrant at first glance, despite China’s sharp economic slowdown.


But only a few cranes — those that are building projects backed by the national government, including a high-speed rail line — are floodlighted and busy far into the night. Far more numerous are the cranes above skeletons of high-rise buildings; they move less often by day, and are dark and deserted by night.


The pattern among the cranes of Chengdu’s construction sites is evident across China. As summer fades into autumn, Beijing is stepping up investment in a bid to rescue the economy, but consumers, businesses and debt-burdened local governments across the country are showing little interest in spending.


A welter of economic data released Sunday by the National Bureau of Statistics showed the extent of the problems. Investment in new buildings and other fixed assets is in the doldrums. Manufacturers are retreating from ambitious production targets as they struggle with bloated inventories of unsold goods. Even the service sector, still underdeveloped and widely seen by economists as full of potential, is showing signs of distress.


“Business is slow these days — just look around this shopping center, there are so few people walking around,” Zhong Yongping, a beautician in central Chengdu, said Thursday as she woke from an afternoon nap taken while waiting for a customer to show up.


Industrial production grew 8.9 percent in August from a year earlier. That was even slower than economists had expected and was the weakest pace since May 2009, when the global economic downturn was in full swing.


But the real problem, as signaled by the slow-moving cranes at high-rise buildings in Chengdu, lies in fixed-asset investment, previously the mainstay of the Chinese economy.


“Construction is slowing down,” said Zhao Chenzhen, a young electrical worker, as he and others in hard hats left a darkened high-rise construction site in Chengdu early Friday evening.


President Hu Jintao said in a speech Saturday at the Asia-Pacific Economic Cooperation forum in Vladivostok, Russia, that the Chinese economy suffered from a “lack of balance, coordination and sustainability.” He strongly hinted at further economic stimulus, saying, “We will boost domestic demand and maintain steady and robust growth as well as basic price stability.”


Bankers and executives say that, across China, builders and real estate developers have decelerated construction to the slowest, most cash-conserving pace possible without setting off default clauses on their loans by stopping work entirely and sending away the cranes. That slow pace, done in single shifts instead of three shifts around the clock as in the past, also showed up in national data on Sunday.


Fixed-asset investment grew 20.2 percent in the first eight months of this year, compared with the same period last year. It was the second-lowest pace since December 2002 — only May 2012 was lower, and marginally so.


While even 20.2 percent might sound high by international standards, it overstates actual growth by including the replacement of existing factory equipment and buildings that may have worn out, in addition to new investment. The monthly data also include extensive double-counting, which Chinese statisticians eliminate only in more comprehensive annual data.


The August figure for investment growth was weaker than expected even though the central government agencies in Beijing have started spending more money again. Their investment spending rose last month from year-ago levels for the first time in 15 months, the details of official data from Sunday showed, as Beijing started trying to revive the economy.


Central government investment spending had fallen late last year and early this year as the economic stimulus put in place in 2009 wound down. It is the rest of investment spending that has been weak this summer and that remained so in August. Local government investment spending, for example, grew last month at the slowest pace since December 2001 — and local government investment spending in China is 18 times as large as central government investment spending.