A Montgomery County man who thought he had car trouble discovered a gasoline bomb under the hood of his car yesterday when he pulled into a shopping center to take a look at the engine.

Richard Burlingame Jr., 29, an employe of Digital Communications in Gaithersburg, found a gallon can full of gasoline attached to one of his car's spark plugs by wires when he stopped in the Quinee Orchard Shopping Plaza about 2 p.m., police said.

Police officials, who said they had no suspect in the attempted bombing, said the bomb was designed to be set off by a spark from the car's ignition coming into contact with gasoline vapors.

Police said they were unsure whether a malfunction in the intended bomb or a malfunction in the car were responsible for the bomb's failure to explode. If detonated, the bomb could have caused extensive damage and might have killed Burlingame, police and fire officials speculated.

Police would not say what might have prompted the attempted bombing, and Burlingame could not be reached for comment. Burlingame's mother, Marjorie, said her son called her after the incident. "I asked him, 'Do you have anyone mad at you?' and he said no," she said.

Burlingame, whose roommate said he was attending a softball game last night, grew up in Bethesda and attended Bethesda-Chevy Chase High School. After high school, he went in the Army, his mother said. Burlingame is divorced.

Montgomery County fire and rescue workers disarmed the bomb and removed it from Burlingame's 1966 auto. Burlingame had been driving along Quince Orchard Boulevard, near his office, when he experienced what he thought was mechanical difficulty with the car, police said.