I dont think press diff of 0.3 compared to 0.4 would cause the hesitation at 2000 rpm, for that rpm, the diff would be quite larger, unless ofcourse for some reason the pressure difference becomes erratic around 2000 rpm. The difference should increase smoothly as your rpm smoothly goes up, this happens by reduction in lower chamber pressure (upper chanber pressure is constant between 5.3 and 5.5 bar) as you depress the gas pedal.

The 0.3 vs. 0.4V may cause a difference during startup. Do you have a problem starting the car or idling ?

The hesitation, does it occur around 2000 rpm also when you gradually depress the pedal past it ?

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Saumil S. Patel