Just started getting the same issue with my car a few weeks ago, after it sat for about 2 weeks. Anyway, I put one bottle of lubegard red in, and started driving the car regularly again. Just brought it on a 2400 mile trip (NJ to FL and back) and about 6-7 hours into the drive down to FL, I noticed the rpm jumping completely stopped, now the car drives perfect again. It has been perfect since. Maybe it was just a sticky valve after sitting so long, but regardless its better now.