I picked up a 97 EX 4d 5sp with 120,000 miles a couple of months back and more or less went completely trough it but it had a hesitation in the mid range. Not that it would miss or stall but it just felt flat on acceleration. I check all the usual culprits, timing, plugs, wires, distributor cap, valve lash, new ox sensor and etc. but no luck. Next I cleaned the idle control valve, it idled nice but no love with mid range power. Next up was the air temp sensor, it resistance checked in range so I had a look at the new plugs I put in a few hundred miles ago. The plugs read on the lean side of OK so I assumed mid range was just a bit on the too lean side. Next up was to check the throttle position sensor. They are suppose to read .5v with the throttle closed with a linear voltage increase up to 4.5v wide open. Mine read .25v closed so I pulled the throttle body removed the headless bolts and replace them with allen heads and reset to .5v this did the trick and really improve drive-ability. Note: I set it up with a analog voltmeter and it must have been a bit mis-calibrated .5v, was giving me high idle so I set it back to .46v (on my meter) and all is good. I think these need to be set right at .5v or a bit less or the computer thinks the throttle is open.

Tim