My wife's 2004, 6-cyl. (150,000 miles) TB runs great, with this one exception: While in drive, but stopped and idling at a light, etc. there seems to be a brief "miss" in the engine. Sometimes there are two in a row, but usually just one at a time and it happens every 30 to 60 seconds for as long as it idles. It runs great under power. No codes are present. This has been happening for a few months. I've used additives like Lucas Gasoline Treatment and that seems to help...but when I don't use it, the problem persists. It just started doing it this year. Anyone?