If your car surges at part throttle and only in a certain speed range, there's an easy fix. It is probably not a bad MAF/MAP and probably not a mechanical problem. It is a TCC problem that can be fixed in two easy steps. 1: fix your stock TCC PWM minimum and maximum. 2: disable TCC from locking in third gear.
1: These are the stock TCC pulsewidth minimum/maximum tables. It is (at times) commanding as low as 20% duty cycle. This is what is causing your part-throttle surging problem. Mine was most obvious with a duty cycle of 40-45%.
Here is the fixed TCC pulsewidth table. 90% minimum and 100% maximum will completely eliminate your problem, if it was indeed caused by the TCC PWM.
2: Once you change the TCC PWM problem, you're not done. Changing those tables will introduce a neck-snapping lock in third gear that will make your car buck like a manual transmission that you let off the clutch too quickly with no throttle. It wasn't noticeable in fourth on my car because the torque convertor locks as the car shifts into 4th gear. So our next task is to disable the TCC from locking in third gear. That can be done here, in the tables highlighted red:
Once done you should have something like this:
YAY! NO MORE SURGING! I chased this problem for more than a year over-thinking it. "Is it my unfiltered card-style MAF? MAF-only tune? Injector offsets got changed somehow? Spark plugs? O2 sensor? Voltage surging?" Nope. Just the TCC PWM.