I’ve just got myself a nice tidy Mk2 Ibiza 1.8 16v GTi as a runabout. I'm having some problems with the SEAT immobiliser. The car has a fancy after market alarm / immobiliser which is working fine but the SEAT immobiliser is still operating and causing problems. Sometimes the car will start but cut out after a second, after another attempt the car normally starts fine. The other day it just wouldn't start at all. I tried locking the car up again and unlocking it as well as many other different ways of alarming and disarming the car but all to no effect. I even tried disconnecting the battery for a while and reconnecting it hoping something would reset itself but this still didn't help. I plugged VAG-COM in and it came up with an error something along the lines of "car failed to start due to immobiliser". I reset the error codes and it started on the second attempt and the error reappeared. The key I have is new non-SEAT key which was cut as the previous owner thought he had lost the original SEAT key so he had the immobiliser and key all re-programmed at SEAT. Could this be the problem? Could it be a loose cable? I do have the original SEAT key which was found after getting the new one, but unfortunately it is no longer matched with the car's immobiliser so does not work. Trying this key actually does exactly the same thing as when I have the problem; the car starts for a second and then cuts out. Any suggestions?