Conditions for Setting the DTC
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
The ECM detects a specific cylinder misfire rate of greater than 30 counts in less than 17 engine revolutions, and P0087 is set. The condition exists for greater than 4 seconds or for a cumulative of 30 seconds.