The hesitation problems have been reported by owners of Lexus ES330 models made between 2002 and 2004 the Toyota Camry and Highlander and other Toyota and upscale Lexus brand models equipped with the same five-speed automatics.
A search of NHTSA records and interviews with Consumer Reports magazine also show owners of other car makes are suffering from the same hesitation problem, including BMW's 3 Series, Ford Explorers and Escapes, and Dodge Durango 4x4.
David Champion, senior director of Consumer Reports' Auto Test Center in Connecticut, said the magazine's testers have encountered the same problems in the Audi A6 2.7T, the Audi Allroad, the Mazda6 equipped with the V-6 engine, and the Volkswagen Jetta 1.8T.
Spokespersons for those companies could not be reached for comment.
What makes the issue perplexing is that no two models of a given car brand may have the same problem. Some owners of the makes involved say they've noticed nothing, while others will say the problem is chronic.
One Lexus dealer, for instance, has said he was able to duplicate the problem only on a few of the cars on his lot, while many others didn't have the problem at all.
The problem involves the transmission gearbox electronic control unit and the engine management control unit, Champion said.
"It's the way in which the transmission gearbox electronic control unit talks to the engine management control unit. The integration of the two systems will allow the transmission to function in the right gear and the engine to provide the power instantaneously in a smooth fashion," he said.
"When you accelerate, the gearbox may change down a gear or find the right gear, and to make the transmission takeoff a smooth one, it retards the ignition to reduce engine power. Unfortunately, while the control unit works out what it's supposed to be doing, you're putting your foot on the accelerator. It can lose its way and doesn't energize the engine and transmission quickly enough," he said.
