A friend of mine had an 09 TL and he had similar problem it turned out to be his PCM (powertrain control module) but you really need to have it diagnosed to be sure. that can be pretty expensive replacement.check to see if youre still under factory coverage and if u r then have it fixed ASAP!
RepairPal Certified shops can diagnose and repair your 2008 Acura TL. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.