Assuming the engine starts well and runs fairly smoothly, lots of things can cause a lack of power and mostly this can be cured by carrying out a thorough maintenance service.
If that doesn't provide a cure the next step will be to check the fuel pressures and injector spray patterns.
It is also possible the exhaust could be strangled because of a partially blocked CAT.
Answers & Comments
Assuming the engine starts well and runs fairly smoothly, lots of things can cause a lack of power and mostly this can be cured by carrying out a thorough maintenance service.
If that doesn't provide a cure the next step will be to check the fuel pressures and injector spray patterns.
It is also possible the exhaust could be strangled because of a partially blocked CAT.