I am starting to notice that while sitting in slow lines like a drive thru blue smoke coming from my tailpipes. The only times it is present is after idling a couple minutes when I give it gas to let the clutch out in 1st gear. Is there anything other than worn rings that could be causing this? Is a complete engine rebuild in the near future? It does not smoke while driving only when I accelerate after idling for 3-5 minutes.