AlliedModders - [ H3LP ] Velocity by angles

Hello, I'm trying to set velocity by the key the player is pressing. I tried this, it's working but not properly. When I set velocity to sides (left and right) the player moves normally however with a small speed applied down. Basically it's walking diagonally.

Code:

velocityByAngles(Float:vAngles[3], iAngleVector, Float:flSpeed, Float:vVelocity[3])
{
    static Float:vVector[3];

    angle_vector(vAngles, iAngleVector, vVector);

    vVelocity[0] = flSpeed * vVector[0];
    vVelocity[1] = flSpeed * vVector[1];
    vVelocity[2] = flSpeed * vVector[2];
}