Legacy 2005 estate management light

[jrrc]

My engine management light comes on randomly ,mostly it continues to drive normally,sometimes it goes into get home mode or when in neutral the revs soar.

I had it interrogated and a fault code P2138 ref throttle position sensor fault was flagged.

Garage advised replacement of throttle body and/or .rthrottle pedal.

These amount to more than the cars value the throttle pedal is cheaper but it may be the body/

The car has done 108000 miles and has been serviced regularly.

Has any one met and dealt with this problem and can point me inthe right direction and can any one say which component is most likely at fault.

 

engine is 1994  chassisJF1BP5KL54G

Thanks