im in my 86 rx7 and im driving down the road at 3500 rpm and the car just cuts off, dead, cant get it to start. its had a rebuild about 20k miles ago with 3mm seals, car isnt what u would call good shape but it ran. and i know i havent blown the motor, i changed spark plugs check everything.. what can i try that would be stoping it from starting besides a blown motor.