I have a 1988 Honda Accord 2.0L 12v (Non Injection). The car seems to run smoothly up to about 45/50 mph but at around 60/65mph the car starts to misfire slightly but enough to make the car jerk uncomfortaby. I have changed the plugs, leads, dizzi cap, rota arm, oil and air filters but this has made no difference. Any help greatfully recieved.
Nick

 

You could do a cylinder balance test to determine which cylinder is misfiring or if it's a global problem affecting all cylinders. You brake torque the motor to the RPM of the miss and have someone pull the spark plug wires one at a time using the all plastic pliers made to prevent shock and see which cylinders or cylinder makes the least amount of change. I would suggest have the vehicle in Reverse while holding the brake rather than drive.