I have a 1999 4runner sr5 4x4 with about 63k miles on it. I just drove it all the way up to Michigan from Florida with zero problems. However, since getting into the cold up here, which may be unrelated, the transmission has started acting up. It seems to be specific to only one situation...

If I roll to a stop sign and brake, then get right back on the gas as I come to a complete stop, the engine revs and the transmission sort of seems to pop out of and back into gear. The first few times it happened, I thought I had just stopped on a patch of ice and gotten wheel spin. The next day it warmed up and dryed out a bit though, and it continued. It never slips in any gear and all shifts are smooth as silk. It does not happen at every start, and does not seem ot be restricted to cold or warm operation. Any clues guys?

Thanks!