1985 sedan deville oil light

i've got a deville here with the ht-4100 and i've heard some pretty bad stuff about this engine. when i'm sitting at a stop sign or something like that idling, the oil light flickers on and off, sometimes its on steadily. but only when its at idle. once i start goin again it shuts off. it also idles a little ruf like its about to die and then it hesitates when i give it gas. so after hearing about this engine i got worried. is this normal or is there something i need to fix? thanks for your help.

The 4100 is a good engine, BUT, it's all aluminum, and doesn't take kindly to overheating as well as a cast iron motor. Do you know the history of this car?
Oil light on at idle could mean low oil pressure; not good. But it could also be a bad sensor. Seen both cases. Yea, you have reason to worry, but have the pressure checked out with a real gauge, or replace the oil switch just for grins.
Rough idle could be anything from a dirty throttle body (or is it a carb on a '85) to a vacuum leak or poor compression in one or more cylinders.