Service Engine Soon?

[Baron Von Buick]

My service engine soon light comes and goes, how can i check what this is without a scan tool? it only comes on when im not driving (in park or nuetral) and it never comes on when the car is warming. I only see it when the car is warm and only for maybe like 3-4 mins. Any ideas?
Thanks
Patrick

 

[b4black]

Probably an O2 sensor since it goes on and off. Try this page:
http://www.gnttype.org/maint/malf.html