Sometimes, during driving, the engine does'nt go beyond 2.5k rpm even on fully pressed pedal. Even at 2.5k rpm engine sounds like running on high rpm. After 4, 5 kms it runs like normal. In normal condition car accelerates perfectly but whenever I reduce speed and then accelerate, the problem again appears. I am facing this issue from its last tuning.
Mechanic told me that it can be due to fuel pump malfunctioning. May be fuel pump stops and then starts after some time. But I think its not possible because my car does not stop but runs on almost 2.5k rpm for several miutes. It means fuel supply is Ok.
What can be the reasons of this problem?