Q: My car acclerates fine but is hard to accelerate after driving for some time, even while flooring the gas pedal.

If the poor acceleration is intermittent, that suggests a cause involving an electrically controlled component including sensors that send data to the PCM. To diagnose this, a real time scanner is applied to view actual engine operating parameters during the reduced power or reduced acceleration incidents. That exam should reveal components operating not as commanded. It might also be necessary to monitor other systems not on the scan tool such as fuel pump output pressure. If a fuel pump is not functioning properly, that can cause a loss of power. To get the fault pinpointed, the recommended service is a reduced engine power diagnostic. Here are some of the possibilities that YourMechanic dispatched technicians would consider in a reduced power diagnostic:

Defective throttle position (TP) sensor
Defective oxygen sensor
Defective accelerator pedal position (APP) sensor
Loose or damaged wiring
Defective throttle body
Defective powertrain control module (PCM) (not typical; ONLY if a long, long list of other possibilities is ruled out)
Any fault/error that will affect drivability function
Any fault/error that will affect vehicle performance
A fault/error in the emissions system
A fault/error in the throttle control system
A fault/error in the transmission control system

If you request the recommended diagnostic the mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.