Considering you're going to send your throttle body out for check up and maybe reman, you might want to check 1 maybe 2 vacuum hoses.

One is about 1" long and connects the two parts of the flap housing.
When you remove the plastic intake to the throttle body you'll see this pik

http://www.peachparts.com/shopforum/attachment.php?attachmentid=32996&d=1146490401

The flap housing is to the right. 4 bolts (2 under the plastic caps and 2 more further to the right.) Wiggle and the flap assembly will come off.

I'm a little vague on the following, because I was so excited to instal my remaned throttle body. ... I think there is another hose that comes off the (lower rear passenger side) of the throttle body (sorry I don't remember where it goes).

Obviously, if either hose is dried out or cracked, a bad vacuum could affect the performance.

Bob
PS I also had a reman done by 4Mercedes.com.
PPS Don't forget to disconnect the 3" link (ball on each end) from the throttle body and yes, the throttle body does come out between the 3 and 4 intake tubes, but it takes a bit of twisting.