i have had my blazer for over a year now and when i bought the check engine light was on.It stayed on for about 3 months and then one day we were 4x4ing and driving it hard and the light went out.now 7 months later it comes now and then but when i shut it off it goes out and sometimes it will stay off for a couple of days or a week before it comes again.o2 sensor?

 

Until you get the code read and let us know what it is, we are absolutely helpless.

 

thanks thats what i thought i will let you know

 

so i read the code and it ended up being the mass air sensor.i should have known because i just changed the intake gaskets and before i did it i took out the airbox and plumbing to see if i could see the leak and started the truck.and the other code was my catalytic is getting bad.