These suffer with air getting into the fuel system via the center pipe on the fuel filter and o ring on the left side pipes on the filter.
Ideally you need is scanning to see if there are any codes but if it won't rev past 3000rpm then check the brake light switch and clutch pedal switches are correctly adjusted as these will restrict the revs when they don't switch.
Press the pedal down and pull out the center part of the switch, it will click as the arm extends, then slowly release the pedal to push the arm back in to the correct position, same for the clutch pedal.