What would cause my C6 to not want to shift from 2nd to hi right away? I have to let off the gas before it will finally shift otherwise the engine will rev. From 1st to 2nd its fine. I had it rebuilt in '91, put about 4000 miles on it and parked it in '93. It had sit until now. I've changed the fluid and filter, checked the fluid level, its fine. Its all stock except for a B&M shift kit. Would sitting that long hurt anything? Does the vac. modulator have anything to do with this? Any suggestions? Thanks, Ryan.