The terror suspect accused of plowing a rental truck into cyclists and pedestrians in lower Manhattan drove into the city at least twice in a single day less than a week before the attack — and cops are investigating whether he was making a dry run, law enforcement sources told The Post.

Sayfullo Saipov, 29, used his E-ZPass to drive through the Holland Tunnel twice and his car was seen on the George Washington Bridge once on Oct. 28, according to the sources.

Three days later, Saipov drove into the city on the George Washington Bridge, then plowed into nearly two dozen people in a bike lane on the West Side Highway.

Authorities said Wednesday that he’d planned the attack, which left eight people dead, for “weeks.”

“It appears that Mr. Saipov had been planning this for a number of weeks. He did this in the name of ISIS,” said John Miller, deputy commissioner of intelligence and counterterrorism for the NYPD.

His attack was straight out of the ISIS playbook, he added.

“He appears to have followed, almost exactly to a T, the instructions that ISIS has put out in its social media channels before with instructions to its followers on how to carry out such an attack,” Miller said.

Saipov spoke on the phone to several people in New Jersey and Florida just prior to the carnage, sources said. Authorities are now looking to interview those people.

Police found “multiple knives” in the Home Depot pickup truck that Saipov rented in Passaic, NJ, about an hour before the attack, authorities said.

There was also a handwritten note in Arabic that praised ISIS.

“The gist of the note was that the Islamic State would endure forever,” Miller said.

One of Saipov’s neighbors in Paterson, NJ, said he often saw the suspect driving in a Home Depot truck with two or three pals.

“I haven’t seen them since [the incident],” Carlos Batista, 23, said. “They need to look for those people, question those people, because they’d be with him every day. They’d know what he’s thinking.”