Temperature sensor probs.
 

Hi 2 all
I have a 2002 lightning.My "service engine soon" light illuminated so I've had it "plugged in" and according to the electronic wizardy its( I think )the head temperature sensor thats playing up.I know its located under the inlet manifold and its saying its running cooler than what it actually is by about 30degrees.According to the chap who is going to be repairing it ,it is a fairly big job.Anybody know how long this job should take?
Many Thanks
Scorcherf150