What could be causing a miss at idle but isn't the following:

- Plugs or plug wires
- Vaccum line leak
- burnt valve

8v, 91, auto, everything (to the best of my knowledge) functioning normally?

I occasionally get a trouble code warning light, but stopping and shutting off the engine clears the light off.

Any thoughts?

What code is it ? and it could be an internal vac leak like an egr valve, or a dirty dist cap, ect.

You didn't supply the mileage, but I would
say it's a burnt valve or worn rings.

How do you know the valve/s are not burned?
Burned valves are common in an engine that
doesn't get it's valves adjusted on a regular
basis. When was the last time the valves were
adjusted?

Have you done a compression test? What are
the cylinder pressures?

Wild

Thanks for the help,

the motor has 145,000km, but is in excellent shape.

Valves were just adjusted, I had a oil leak fixed (valve cover) and the valves were adjusted.

A compression test reveiled a good 170 on each cylinder.

I don't know what code it is, I'm going to get OBD'd next week. Will the computer store the code for a while? It only comes on once every 2 weeks'ish...

The EGR appears to functioning normally. So I am told. I can pull a wrench, but my mechanical knowledge is limited. I had a good mechanic do some of the more complex work (like try and track down the miss) a while back.

Thanks again

My guess is an intermittant ground wire. 

Them TracKicks will do that with grounding problems.  Look for ground wires attached to the body in the engine compartment and tighten them down...

...then again, I'm the guy who mistakenly said that all Samurai axle U-bolts are the same size.    And I even installed my own SPOA!