[Prerunner1982]

When the check engine light comes on, isnt it suppose to stay on until it is reset? The check engine light on the wifes 87 GMC will come on every 4 days to a week.. but as soon as you turn the truck off then back on, it goes out for another 4-7 days... any ideas? i havent been able to get it checked, everytime it comes on i am on time restraints to be somewhere...