On Board Diagnostics generation II (OBDII) provides more information and more accurate fault detection than previous systems. One of the new fault detection programs is cylinder misfire detection. An OBDII vehicle should provide specific cylinder or cylinders misfire and detect random cylinder misfire, but don't rely on it to diagnose all of your ignition faults.
The ignition screens below show an OBDII vehicle that had a major ignition misfire under heavy load and there were no misfire fault codes detected.
Normal during idle
Normal during acceleration
Misfire during acceleration
This 2000 model Ford produces three firing events during idle speed and only one firing above idle speed. The middle screen shows a normal secondary pattern during acceleration. The right screen shows the misfire. The Omitec PDA detected 31 misses out of the 50 screens in this recorded file. The record and playback function is a power feature that will help you pinpoint and document malfunctions.
