1997 Honda Accord V6 hesitates while in D4?

I bought a 1997 Honda Accord V6 a few months ago, it has 168,000 miles on it automatic transmission. I had a bunch of work done to it, the mechanic said everything was in great shape. The day after I got it back from the mechanic it was stolen & in a high speed chase. We got it back the same day & had to put more work into it (all cosmetic though). Now, after owning the car for about 3 months, I have been able to drive it for the past 3-4 weeks. I have noticed that while I am driving on the freeway in D4 the rpm gauge dances all over the place & it feels like it is hesitating. It doesn't do it all the time & there are no lights flashing, everything else seems to be fine & it drives just fine in all other gears. Any ideas on what could be wrong??