Engine lull/lurch in '02 Tacoma?

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Just wondering if anyone has a lull/lurch in the engine during takeoff. I have an '02 Tacoma Pre-Runner with 62,000 miles on it and bought it used a year ago. In the last 2 weeks I noticed a lull in the engine after braking and then hitting the gas again. I didn't come to a complete stop though when it did it. Today, while sitting at a red light, with the truck in drive, the truck seemed like it slipped into neutral just for a second becuase the truck felt like it rolled back just a little. Anyone experience this and should I be really concerned? Not sure if changing the tranny fluid would help or not. It hasn't been changed since I've had the truck, not sure about its past service record. It has been checked with every oil change but hasn't been recommended. Thanks for any help/advice.