immobiliser problem?

[klukewakes]

anyone had this problem?i have tuscan and just recently the immobiliser seems to be playing games with me.when i un-arm the alarm an turn the key the fuel pump does'nt always kick in,if i wait till the lights flash and press the key sumtimes it works but at the moment its not at all,also if i un-arm and wait till lights flash and press key again it does and does'nt work,if i turn the ignition on and off a few times that sometimes does the trick but at the moment nothing is working ahhhh..... i took the car to hhc and when they had it it started workin fine so they said that they could'nt do anything with it other than check the wires n stuff,could it be a fuel pump fault?