1. A system for an engine, the system comprising: a first module that determines an expected response of crankshaft speed due to combustion within a cylinder of the engine; a second module that determines a value based on the expected response and a measured response of crankshaft speed due to combustion within the cylinder of the engine; a third module that estimates an indicated mean effective pressure (IMEP) for the cylinder of the engine based on the value; and a fourth module that selectively adjusts an operating parameter of the engine based in the estimated IMEP.