Immobilizer Issues - Please Help Me

[craigdrums]

Hi Guys, I hope you can help me. I have a 2000 W Galaxy which has been just brilliant until recently. I was driving up the M40 and it started chugging violently then it seemed to sort itself out. It had a service and my mechanic but some fuel stuff in the tank?! the following week the main key stopped working and so I was using the smaller thin key, this was great until a couple of days ago where it wouldnt start all the time. Then I noticed the immobilizer light on the door wouldnt come on and go out (so it would then start) I broke down on saturday and got relayed home and now the red light on the door doesnt come on when I put either key in and turn it although all the dash lights up fine. any advice greatfully appreciated

 

C