1991 grand prix rough idle sputter on interstate

[jdawg53]

I have a 1991 grand prix that starts and idles fine at first. After a few minutes, the check engine light comes on and it starts to idle rough. It hasn't died yet, but it feels like it is going too. Also on the interstate it runs fine the first few minutes then the check engine light comes on and it sputters.
I just changed the fuel pump and filter about a year ago.

thanks

[doctorhrdware]

Could be a fuel regulator. You may want to also check the fuel pressure might be the problem also. Just a thought.