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Hesitation and random misfring at high speed are more likely caused by ignition.

Like someone posted, check the plug wells and clean out oil and contaminations. Oil will cause ground faults with the plugs therefore misfiring.

NGK plugs may not be compatible like DENSO plugs. Check gaps to make sure. Clean out contacts.

Check and test ignition cables for potential shorting to ground.

Off brand and counterfeit ignition coils will misfire intermittently.
 

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Engine may be misfiring at high RPMs and not logged by the ECU and you don't notice it.

The 4 cables between the ignition module to the ignition coils may be shorted and arcing at high RPMs. Check them out and separate them from each other and from the engine.
 

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The 3 wires from the Denso O2 sensors are about 5 inches long, so the splices have to be under the car.

You can solder the wires, but I used the splices and taped up with electrical tape. Have not had problems with those splices in years.
 
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