New York's borrowing statute, CPLR 202, states that an action based upon a cause of action which accrues outside of this state , the claim must be timely under both the law of New York and the jurisdiction where the claim accrued.
THIS MEANS THAT IF YOU DEFAULTED(CAUSE OF ACTION) IN A SHORTER SOL STATE,AND THEN MOVED TO NY, YOU MAY USE THE STATE'S SOL IN WHICH THE CAUSE OF ACTION ACCRUED (STARTED) The purpose of a borrowing statute is if you have moved from a SHORT SOL State to a LONGER SOL State,the borrowing statute would allow you to use the shorter SOL as a defense if you are sued, providing that your default occurred in the short SOL State,and also provided that your new longer SOL State had a borrowing statute.
In your case SOL 4 yrs.