CEL comes on while coasting

[DirtySeattle]

Whenever I am coasting in neutral or just sitting at a light, my E30's CEL comes on. It goes away as soon as I give it gas, but anyone know why this is happening?

[Jaxx_]

vac leak? Do you have oscillating idle?

Otherwise, maybe tps? I have no idea when it comes to m20 management, so I'm picking at straws, but your initial description leads me to ask these questions.

[DirtySeattle]

All of those could be possibilities, it just started happening a week ago, and every once in a while it has a rough idle.

[dnguyen1963]

rough idle = vacuum leak