Chrysler LLC will decide within the next few months whether it will build a new midsize car on its own underpinnings or whether it will use another automaker's engines, frames and transmissions, a top executive said Sunday.

Frank Klegon, the Auburn Hills automaker's product development chief, would not identify which companies are in the running to build the car's underpinnings, but he said Chrysler had initial discussions with General Motors Corp. last year when the two companies were talking about GM acquiring Chrysler.

Executives from both companies have said there are no discussions under way at present on merging the two companies because GM is focusing on its own financial problems.

Chrysler's two midsize offerings, the Chrysler Sebring and Dodge Avenger, have not sold well compared with their competitors, mainly the Toyota Camry and Honda Accord. GM's Chevrolet Malibu also has made inroads in the midsize segment after being revamped for the 2008 model year.

Last year, Chrysler sold about 48,000 Sebrings, down 38 percent from 2007. It sold roughly 62,000 Avengers in 2008, 26 percent fewer than the previous year, according to Autodata Corp. By comparison, Toyota sold 436,000 Camrys, making it the best selling car in America.

Chrysler executives have conceded a need to upgrade the cars' interiors and have said they'd like to change the exterior styling.

Chrysler also may be in discussions to build the new midsize car on a Nissan platform. The company already has plans to build a subcompact for Chrysler to sell in the U.S., and Chrysler is developing the next generation Titan pickup truck for Nissan.