97 GTX surges and tach jumps

[herb165]

i replaced the complete fuel system,hose,selector switch,water/fuel separator and had the carbs rebuilt at a local shop,but once i put it in the water,it runs good for about minutes and a half and starts to surge and the tach jumps from 4200-5200 and 4500-5700.It just feels like it revs and drops picks up and does it again