I have a 2000 Pontiac Firebird, what causes the reduced power engine light to come on ?
When the vehicle computer receives voltage signals that are abnormal it will come on. If this seems to only occur when the engine is cold. Try letting the vehicle run till it reaches normal operating temperature ( between 180 and 220) before driving it and see if it runs OK, You may have a faulty engine temp sensor that is sending the wrong information to the computer. Does the check engine light come on??? If so extract the codes and this may help narrow down the problem.