Most often it's an oxygen sensor, but it can also be a number of other components including : plugs, plug wires, burned valves, vacuum leak, dirty/faulty idle air control valve or dirty air filter.
Does the engine light appear with car running? If so, scan for diagnostic codes. If not, you may want to start with a good tune up which normally includes plugs, wires, fluids, and filters.
Hope this helped.
SPONSORED LINKS
Thursday, December 4th, 2008 AT 1:11 AM