Sorry to make my first post a problem (and a long winded one), but I could use some sage advice!
To give some history.
I have a 2.0 JTDM 159, its been regularly serviced and maintained by local alfa specialists, had a couple of jobs done under warranty (power steering pump, back box due to rust). It's now out of warranty and has started with an odd problem. Its fast approaching 100k Miles.
Since new its had an occasional struggle picking up on power low down in the revs, however I've always understood that as one of the "joys" of this model. Sometimes scares the crap out of me at a roundabout when i put the foot down to pull out into a gap and the car struggles forward slowly until about 2000rpm.
Anyway, recently it started to chuck out black smoke (blinding anyone behind) and bunnyhop when I put my foot down to overtake on the motorway (over 3-4k revs). It was also terribly lumpy at idle, it was clearly not happy. My initial thoughts were a blown turbo hose, however on inspection I saw no issues other than what looked like grease around the manifold vacuum inlet, the car had also not thrown any error codes.
I took it to the local specialists who replaced 1 of the injectors which according to computer was almost constantly wide open. This was thought to have fixed the problem as the lumpyness was gone and I drove back from the garage fine, the next morning however it managed approx 2 miles before stalling at a set of traffic lights.
The car battery/alternator was fine as radio etc working, the car was turning over but just would not kick in, after about 15 minutes I tried to start it again, it kicked in, managed 3 or 4 seconds of running then stalled again. The local specialists kindly came out and picked the car up and said that the fuel kill switch had been triggered. As a result, they were able to simply drive the car back to the workshop. (~3 miles)
Since then they'd had the car for a week trying to troubleshoot the problem, however as no error was being throw (apparently it has cut out on them a couple of times on test runs) they were unable to identify the fault. They've tried draining the fuel tank (though it had not seen a petrol station with me for almost a week and had driven 3 or 4 40 mile journeys to and from work since, unless they accidently put something duff in.....) I generally use either asda/bp regular fuel depending on price, but every 3 or 4 fill ups I brim the tank with Shell V Power+. Anyhow, this hasnt solved the problem and the car continues to cut out.
The next suggestion by them as it was apparently knocking (Its now back with me on the drive and seems to be fine at idle) was to replace the remaining 3 injectors, which I cannot at this point honestly afford to do (at £300 odd each, they're not cheap!), especially given there is no guarantee this is the cause since there is no error code. My main concern is that it wasn't stalling before the original injector was replaced, only since the repair, and i'm not sure why 4 injectors would fail/need replacing at the same time?
As a result I've had to borrow a car from a friend and take my car back, hoping its something cheaper I can fix myself. I've managed to drive it back from the garage without any issues, I didn't want to push it however so kept the revs low and havent been out on a proper run yet.
I'm handy with a set of spanners and have on the recommendation of mechanic friends ordered a new crank sensor which we intend to fit at the weekend and give it a test drive.
If thats not my culprit, suggestions/questions/answers please?