CANTON, Ohio—It was a frustrating problem that almost made John Gaddis give up on his customer's Chevy Impala.
The car would work fine in the service garage of Progressive Chevrolet, a car dealership in Canton, Ohio, where Mr. Gaddis is service manager.
But then he would release it back to the customer who, two weeks later, would send the vehicle back on a tow truck with the same "engine cuts out" condition.
All the best on-board technology didn't register a single problem code. The Impala's owner demanded a replacement.
But Mr. Gaddis, whose dealership traditionally ranks high in customer satisfaction among Chevrolet dealerships nationally, couldn't give up on an intermittent complaint without a justifiable explanation.
"If we can reproduce the problem, we can fix it," Mr. Gaddis said. "If we can't, it's worse than finding a needle in a haystack."
Intermittent problems present one of the biggest problems to time-strapped techs, be they in car dealerships or independent service shops.
Many dealerships don't charge customers when they pay to solve a driveability problem and the vehicle comes back repeatedly for the same complaint.
Diagnostic difficulties are so troublesome that dealers and managers attending the recent 2000 National Automobile Dealers Association Convention and Exposition said their No. 1 interest at the exposition was service department tools and equipment, said Kara Thorp, an NADA spokeswoman.
An occasional "engine cuts out" complaint could indicate a failure in the electronic control module, fuel injector, wiring harness, relay switch or a troublesome cell phone that causes electromagnetic interference.
An astute technician at Progressive traced the Impala's errant circuit on a wiring diagram and caught a malfunctioning relay switch.
Each of the Big 3 are beefing up their diagnostic capabilities. Ford Motor Co., for example, introduced software into its on-board computers in 1999 to detect system malfunctions quicker.
"Technicians find an extensive list of parameters that get stored in the powertrain module," said Dave Van Asselt, global diagnostic strategy supervisor for Ford.
"They can hook up diagnostic equipment and communicate as though they were on the scene when the breakdown occurred."
Ford also introduced a worldwide diagnostic system for all its product lines, a portable instrument that provides a faster sampling of data from the on-board computer. It can detect even a momentary inconsistency.
Last November, Ford introduced a new tip system through its satellite communication network that gives updates on problems encountered by Ford's technical assistance department, the group that receives phone calls from technicians nationwide.
DaimlerChrysler A.G. beefed up its Web-based technician training this year to help technicians improve their capabilities of finding intermittent complaints. It also introduced new customer-service training.
Dave Shafto, service director of Progressive Chevrolet, doesn't like that General Motors Corp. closed its regional training centers and moved service training to satellite video delivery in 1999 because "watching a complicated procedure on video puts our guys at a definite disadvantage."
That aside, Mr. Shafto said he has a realistic view of the difficulty with intermittent problems:
"We'll never solve the intermittent problem completely," he said. "Just about the time we solve one set of problems, the manufacturers introduce vehicles with even more bells and whistles that add complexity to our repair function."