This is a 2006 R-50 JustaCooper, manual gearbox with 57K miles. The car always starts quickly, but today it cranked quite a while before starting. Driving at 50 mph, it lost power to the point that I thought the engine had died. Pressed clutch, it was idling close to normal. Both the "Service Engine Soon" and EML lights were on. With foot to the floor, the tach showed 1600 RPM. I basically idled home; 3rd was good for about 30 mph.

Turned the engine off, hooked up my OBD code reader and got only code P0638 - "Throttle Actuator Control Range/Performance (Bank 1). Blipped the throttle, it's back to normal with the "Service Engine Soon" light on but the EML off, and it drove normally around the block.

After running errands on the motorcycle, I restarted the car, idle was now very bad, both the "Service Engine Soon" and EML lights were on, and foot to the floor was good for 2000 RPM. The third time I restarted the car, the EML light was off, and it had normal throttle response.

Rechecked OBD codes, still shows P0638, plus P1125 - Throttle Position Sensor A and B Range/Performance Small Error and P1229 - Throttle Sensor Adaptation Failure.

My first thought was probably the accelerator pedal position sensor, but the two new codes have me wondering. Has anyone had this issue on a JustaCooper? I see a AAA tow in the near future...

 

I have the same symptoms and codes with my 2003 Cooper S. What was the problem in the end? Throttle body?

Thanks