Here is the checklist of stuff that caused that sort of issue in my 86:

Pull the vacuum line off the Fuel Pressure Regulator, you smell gas, change it out. (that was my biggie)

Check the wires and plugs replace as needed.

In Tank pick up pump may be going out, easy to change and not expensive.

Look for vacuum leaks and for nothing loose. Be sure to check the underside of the large air intake hose in the corrigated section. The oil and gunk are actually normal.

Clean the throttle body and replace the gaskets when you reinstall it.

Bet one of those will solve your studder leaving the light.

Does you idle have a little hitch in it or is it smooth? Smooth would make me take the vacuum lines off the list.

Good Luck and Regards,

Paul