TBS= Throttle Body sync and TPS= Throttle Position sensor. Both (particularly the TBS) have a reputation for going out of spec over time and can cause rough running. TBS is easily done by checking the vacuum in each of the throttle bodies by using vacuum gauges, and adjusting one relative to the other so they both flow the same amount of air. The TPS is an electronic 'widget' attached to the side of one of the throttle bodies and can be easily checked by using the dealer mode function. If you want to know how to check both then have a search around the forum, there are a few of threads on the subjects. If you don't have a set of gauges get the dealer to at least check the TBS, although with the amount of work you've had done I'd be surprised if they haven't done it already.
