I have a 73 240Z with Webers, I have recently replaced the distributor, mechanical fuel pump, and electric fuel pump. But I am still having problems. The car drives fine in town, but on the freeway around 70 MPH or higher the car begins to jerk forward, I will let off the gas and it will drive normal again, but then a couple of minutes later it will start jerking again. It jerks the most when going up hills and grades. Any help would be greatly appreciated. Thanks.