1997 Pontiac Firebird engine light on and code. What do I do

How long ago was the lasrt tune up? Always go with the basics, youll have to check em anyway! To check for vacuum leaks:get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs!
https://www.2carpros.com/car_repair_video/test_engine_ignition_system.htm
Check #4 this way!