Ok, this problem cropped up a few days ago and has been getting progressively worse. When the car's running, the main relay will click at a steady rhythm. Imagine counting slowly in your head - 1, 2, 3, <click>, 1, 2, 3, <click>. Each time it clicks, the car misses obviously, creating an annoying bucking-bronco feeling when driving, and an equally annoying stall when idling.

When it first started, it only happened at low RPMS at light throttle. Then it was any rpms at any steady throttle. Now it's doing it while idling and accelerating. After it started happening, I replaced the distributor with a brand new one, and today I replaced the main relay with a brand new one. I also replaced the spark plugs on a whim. And it's only been getting worse.

The rhythm is independent of speed, RPMS, and AFR. Every once in a while, it will break the rhythm and go haywire with the clicking for a second, then immediately fall back into step. There are short stretches (5 seconds or so) where everything's fine, no clicking.

I'm out of ideas, and the Expo is 4 days away. Help!

Car is a CRX, engine is an obd-0 b-series vtec.