2011 Ford Mustang struggles above 1st gear

what cou8ld be the problem I have a manual 2011 mustang 3.7l and 1st gear I can floor it to any rpm range along with 2nd 3rd and forth it struggles to go above 3 x 1000 rpm s

Is the check engine light on?

No there is no lights

Your vehicle has a drive-by-wire throttle system.

This means that instead of having a throttle cable between the throttle pedal and the throttle body, your vehicle has an accelerator pedal position sensor,

that sends a signal to the computer, and the computer takes that signal and operates the electronic throttle body.

Remove the intake hose from the throttle body.

Have a helper turn the ignition switch on without starting the engine.

Have the helper slowly press the accelerator to floor while watching the throttle plate.

Does the throttle plate open completely?

If not, the problem is with the electronic throttle system.