I know what a potentiometer is,but I'm at a loss to think what u mean.So if you'r going to diy it,then go to argos and buy their rac code reader.£40.(garage will easilly charge you this much) and follow directions and plug it in and read the fault codes stored in the memory.once u have the fault codes then u will have a much better chance of fixing the fault.oh and next time,make/model/engine size,cc/year and fuel type please,and is the engine managment light on.
caine
August 2008