Hi, I was hoping someone could assist me with a drivability issue I've been having. When the car is off, the gas pedal is easy to depress, and entirely normal, however when the car is on, the pedal becomes difficult to press, and if i press too much it will gun it. The car in question is a 73 z, l28, flattop pistons, mild cam, roundtop su's, throttle cable conversion. Thanks for any help, I'm hoping its something dumb and simple. Also, the car is running a little rich as of the moment if that matters (needa tune the carbs)