If a tune up was just done and this problem just occurred after the tune up I would go back to the repair show that did the work and get them to make sure they didn't inadvertently knock off a vacuum line or sensor connector. If the tune up was done to address this problem in the first case, and the problem is not a slipping clutch or transmission issue, I would verify the Check Engine light is not on during a rad test. If it is on I would retrieve stored trouble codes and follow the indicated trouble shooting path for the item the trouble code was stored. If no Check Engine light was on I would still plug in a scan tool to the diagnostic socket under the dash and monitor engine sensor data to see how much air the computer thinks is going into the engine (some Toyota/Lexus products had air flow meters that got dirty and caused a lag on acceleration, poorer fuel economy). I would also perhaps check fuel pressure and delivery if on a road test I felt that needed to be verified.