A method for determining a misfire condition includes receiving crankshaft acceleration data. The method further includes routing the received data through at least one of a plurality of processing paths and through a startup path and determining a crankshaft revolution count. The method further includes comparing the determined crankshaft accelerations over the determined revolution count to at least one threshold crankshaft acceleration value over the determined revolution count and determining a misfire condition from one of the startup path and the processing path based on the comparison.