My Truck just started doing this. I hit the on ramp in busy traffic and was surprised when I had no GO in forth gear. got up to sixty mph really well, but it acted like a severe defuel after that. Shifted to fifth and peddled as hard as normal until about 2K or 70mph and then nothing :{ . Engine used to have excellent power up to about 2500rpm but not now. Could a broken governor spring cause this? Sound like I just need to get a 3K GSK. What do you think. and where can I get the best price on the things. 
