147 stalling with immobiliser fault
About a week ago while driving home from work I pulled up at a set of traffic lights, dipped the clutch to take the car out of gear and the engine died. The dash showed an immobiliser fault warning and a key symbol. I tried restarting the car but it wouldn't fire I guess due to the immobiliser. I tried taking the key out of the ignition and putting it back in but nothing seemed worked. I sat there a few minutes looking for the breakdown recovery phone number on my phone whilst trying to start the car occasionally and after a few minutes it suddenly started. It died again twice more on the way home but on each occasions started after a few minutes.
After the first time I drove it for 3 days without issue and then it started doing it again and it's now done this to me 3 times. It's strange that the car seems fine on shorter 5-25 minute trips but not on longer journeys like my 60 minute commute to work and when it does die it's only after I've been driving it for about 45 minutes.
I've had the car error codes scanned and it showed a crankshaft sensor fault which I'm not surprised as it's had an intermittent misfire between 2000 - 2500 rpm for a while now. The garage said they'd replace the sensor and see if that fixed the issue which I'm happy to do as it might well fix the misfire but I really can't see how it will fix the immobiliser issue.
One thing to note is that the blipper does not work on both keys although they haven't for about a year now and I've never had an issue before.
Any help would be really appreciated.