"check engine soon" question??

i have a 94 grand prix (3.4)and of course with the obd system that you cannot use a obd 2 reader or a jumper to read codes with,only a serial reader or scanner,in the past when my light has come on in some of my cars there useally has been a small jolt or hesitation or some noticable difference in performance to indicate that something has happened in conjunction with the warning light.this car has had now for the last three mornings upon starting the car the "check engine light "will come on and stay on for the first 5 to 10 minutes of driving then go off,it doesn't flash and the car is running very smooth like nothing is wrong or tripped at all,it's just the light has formed a pattern of illumating the first few minutes,can anyone tell me what is going on or should i worry that this could be a warning sign of something starting to go wrong,i can't exactly try to read the codes if any are set with the obd setup on it.thanks