you must have the hitachi carb?
i think the idle mixture screw is pinned in place- where the pin fits in a slot in the mixture screw to prevent it from being turned without taking the pin out.
perhaps somebody has been thru the carb and has reset this.
just a thought as i was looking at this on mine when i did an overhaul (i have an '89 1.3L kick) but didn't touch it.
you may be able to lean it out at idle and pass both parts of test?
i live in CA and will have to smog in a few months, and will probably have to put my stocker back on to do it. i use a "no pass- no pay" place. DON'T GET ON THE GROSS POLLUTER LIST! you will have to go to a state run facility for testing(i think).
mabe?
richard