It's just one,sometimes two, happens every time engine is started when temp guage is toward lower end of dial. Lasts until engine reaches normal operating temp, which could be 1-5 minutes, depending on weather or how much time engine has had to cool off from last run. If weather is warm (55deg+), I can start car, run with miss for a short time, then shut off, and let sit for a few minutes. This heat soak time seems to shorten the period, 'cause the miss will leave upon or shortly after restarting. Mark