Yesterday, while in rush hour traffic, I was in third gear at about 25 mph and I noticed that when I gave the car (98 EX w i/h/e) just a little gas, it'd hesitate and lurch a bit until I sped up.

It doesn't happen at WOT and it doesn't happen in any other gear. I just replaced the plugs about a month ago with NGK Rs, but that doesn't explain why it only does it in third.

There's no odd noises either.

Any help would be greatly appreciated!

 

First off, the engine doesn't care or know what gear it's in. The symptom may just be more noticeable in 3rd. FWIW, I had similar symptoms on my '90 Si. (ie. 3rd gear, 25mph, bucking/surging or hesitating. In my case, the O2 sensor output was low and lazy. During WOT, the ECU ignores the O2 sensor output and relies on a preprogrammed fuel map.

 

I understand the engine doesn't know what gear the car is in. However, wouldn't you assume that it would do the same thing in any gear at that engine speed?