starting problem

[robcaz1708]

Hi all my wife has a 2001 1.6 206 it has starting problems it spins over great so that rules out starter we have had the crank sensor replaced and the coolant temp sensor but still have the problem .
It has been on diagnostic machines and no fault code is registered so the garage is stumped I have heard that the imobilser pick up ring is sometimes an issue with these cars , when it does start it runs lumpy does the imobilser just cut out the spark thus allowing for the fuel to still pump in and cause this ?

thanks rob

[GrandadMonkey]

As far as I understand it the immobiliser disables the starter, fuel and ignition.