GM's vehicle sales in China for the quarter ended June 30 dropped 12.2pc, while Ford's sales slumped by 21.7pc. While GM also suffered from heightened competition in its key mid-priced SUV segment, Ford was hurt by the limited new models for customers to choose from.
For the first quarter of this year, Ford's sales in China tumbled 35.8 percent while GM's skid 17.5 percent.
Still, the numbers from GM, the second biggest international automaker in China by sales, and Ford portend more uncertainty for the industry which is trying to rebound from a downward spiral that led to its first annual sales decline last year in more than two decades.
GM delivered 1.57 million vehicles in China in the January-June period this year, while Ford delivered 290,321 vehicles.
China's factory activity shrank more than expected in June, highlighting the need for more economic stimulus amid higher US tariffs and weaker domestic demand.
Annual car sales in China fell last year for the first time since the 1990s, and they are expected to fall this year too.
Sales tumbled 16.4pc in May from the same month a year prior, the China Association of Automobile Manufacturers (CAAM) said.
That marked the 11th consecutive month of decline and followed falls of 14.6pc in April and 5.2pc in March.
US car companies' share of total China passenger vehicles sales fell to 9.6pc in the first five months of this year from 10.9pc in the year-ago period, according to CAAM.
Over the same period, German car makers' share has risen to 23.3pc from 20.9pc and Japanese auto makers' to 21.3pc from 17.3pc.
CAAM is set to announce June sales next week, which industry analysts forecast will be negative.
NEW MODELS
In China, GM has a joint venture with SAIC Motor Corp , in which the Buick, Chevrolet and Cadillac are made.
It also has another venture, with SAIC and Guangxi Automobile Group, in which they make no-frills minivans and have started to make higher-end cars.
Sales of GM's affordable brand Baojun dropped 31.8pc for the latest quarter. But luxury brand Cadillac's sales jumped 36.6pc.
GM sold 3.64 million units in China last year, down from 4.04 units in 2017.
Ford makes cars in China through its joint venture with Chongqing Changan Automobile Co Ltd and Jiangling Motors Corp Ltd (JMC).
It has said it would partner with Zotye Automobile Co Ltd to sell lower priced cars.
The Dearborn, Michigan automaker has been struggling to revive sales in China, its second biggest market globally, after its business began slumping in late 2017. Sales sank 37 percent in 2018, after a 6 percent decline in 2017.
GM, Ford and rivals are launching new models or sprucing up older ones to attract customers. GM has laid out plans to introduce around 20 new models or variants of older ones this year.
"Around two-thirds of the about 20 new and refreshed models will arrive in the second half with a sharpened focus on luxury vehicles and mid-size to large SUVs," a GM spokeswoman told Reuters, adding that more than half of the new launches will be new models.
Ford has said it plans to localise its luxury brand Lincoln in China and would launch more than 30 new models in China over the next three years of which over a third will be electric vehicles.
It has launched new models such as Focus and Territory to boost volumes in China.