Answer by taking a quote from the following article:

Zazi was born in a village in Paktia Province, Afghanistan. He has two sisters and two brothers. At the age of 7 in 1992, he and his family moved to the city of Peshawar in Pakistan where they settled as Afghan refugees. In 1999, he and the family left Pakistan and immigrated to New York City.

On September 10, as he crossed the George Washington Bridge headed for New York City, Zazi was pulled over by Port Authority Police, acting at the FBI's request, for what he was told was a routine random drug search, and his car was searched. They did not find anything of note, and he was allowed to go. Afzali's lawyer later wrote the court: "Even though [Zazi] is not the brightest bulb in the terrorist chandelier, the thinly-transparent ruse of a 'random' checkpoint stop did not fool him."  On September 11, Afzali called Zazi's father. Zazi's father then spoke with Zazi, told him that "they" had shown Afzali his photos and photos of others, said Afzali would call him and he should speak with him as soon as possible, and added "So, before anything else, speak with [Afzali]. See if you need to go to [Afzali] or to make ... yourself aware, hire an attorney." Afzali called Zazi, and told him that the authorities had asked him about "you guys." He also asked Zazi for the telephone number of one of the other men whose photos he had been shown, and set up a meeting with him.  Later that day, Zazi's rental car was towed due to a parking violation, and was searched. Agents found a laptop with a JPEG image of nine handwritten pages on how to make initiating explosives, main explosive charges, detonators, and fuses. The FBI asserted the nine pages of handwritten notes were in Zazi's handwriting.  Zazi called Afzali, said his car had been stolen and he feared he was being "watched", and that the people watching him took his car. Afzali asked if there was any "evidence" in the car, and Zazi said no.  When Zazi realized they were under investigation, the group threw away their bomb-making materials.

Did they find anything in the rental car?
Agents found a laptop with a JPEG image of nine handwritten pages