Ricarr

Have a 2007 Cayman S, automatic tiptronic transmission...car is new to me with app 74000 miles. I notice when driving in automatic mode, at slower speed, the trans lags a bit as described by many, but I really notice a very slight rev... for lack of a better term when the car goes into 5th. The rpm's go up a bit for a split second before settling in, again while in the automatic mode. Does not seem to do it if I am manual mode, shifting thru the gears myself. My mechanic mentioned that he noticed it on a short test drive for a unrelated fix on the car and mentioned maybe a transmission service would remedy the issue. Mechanic said it isn't anything bad enough to show up in the cars computer system. Anyone familiar with this issue or experienced anything similar and/or suggest a remedy? Thank you for any input

PS did the full transmission service and "reset" (the computer i guess?) and didn't help. Mechanic a bit stumped but doesn't think it is a big issue with no errors right now. Mechanic mentioned torque converter and another possible issue i cannot remember right now. Have read about possible vacuum leak as possible cause along with the old get a new tranny....thanks again