No, a private investigator cannot legally tap your phone without your consent or a court order. Tapping someone's phone without their consent or a court order is a violation of federal and state wiretapping laws, and can result in criminal charges and civil penalties.

In general, private investigators are bound by the same laws and regulations as law enforcement officers when it comes to wiretapping and electronic surveillance. Under federal law, it is illegal to intercept, disclose, or use any wire, oral, or electronic communication without the consent of at least one party to the communication. Some states require the consent of all parties to the communication.

Private investigators may be able to legally obtain phone records or other information related to a phone number through lawful means, such as by obtaining a court order or subpoena. However, they cannot intercept or record phone calls without proper legal authorization.

It's important to note that there may be exceptions to these rules in certain circumstances, such as when law enforcement officers are investigating a suspected crime or terrorist activity. However, private investigators do not have the same authority as law enforcement officers and must abide by the same laws and regulations as other private citizens.