Throttling Holden Omega Ute

My 2008 Commodore Omega 3.6-litre four-speed auto ute has a throttle response issue. Sometimes on light throttle when I try at accelerate from around 1500 to 2000 revs the engine doesn?t respond for few seconds. I?ve had it to the dealer three times. The first time they couldn?t fault it, the second time the said they found the transmission range sensor not communicating and they cleared the code and carried out a software upgrade. After that it went well for two weeks, but has since returned. I had it in again last week, but again they say it couldn?t be faulted and I've rebooked it to go in at the end of this month. I?m just wondering if you've heard or know of another Commodore with a similar scenario?