Emissions idiot light

My 1986 Bronco II (6 cylinder, 5spd) has had the Emissions light on for a while. Lately, the car has been bogging down and "bucking", or the rpm's pulsate with light pressure on the gas (whether or not the clutch is engaged). I have heard that there is a silenoid switch, but which one? Chilton's hasn't helped much, b/c I don't know what to replace??

The Solenoid can be found by tracing your Red Lead off the battery. It's on the bay wall. I doubt having a bad one will cause you to run poorly. If the solenoid goes bad, you probably won't be able to start the thing, anyway. (Check the $8 Bronco thread for more info about those.)

If the Emissions light is on, check the Catalytic Converter. Those are designed to collect the engine exhaust, and they will clog. (If it's been 19 years since a new one's been put on, that your most likely suspect.) As you know, the engine is all about backpressure on the exhaust manifold. When the Cat clogs up, you have too much backpressure for the engine to run.

A code scanner for your vehicle is pretty cheap ($20-$40) and worth the investment. It'll tell you why the emission light is on. Even if you don't fix the problem yourself, you'll know what's wrong when you bring it for service. Sounds like your idle speed controller, sometimes called an idle solenoid.