I have a 92 ford ranger that is running ruff.I have had the icm checked but to me it acts like an ignic prob. Any thoughts

Usually, rough running is caused by loose or worn secondary ignition items: worn or fouled plugs, cracked or arcing wires, cap and/or rotor...

However, things like injectors sticking or not being fired, or a worn valve train can mask the symptoms and make pinpoint diagnosis difficult.

As you can see, many things can lead to a "ruff run" condition.
Lots of inspecting to be done before changing any parts.