On Alfa number 15
AO Platinum Member
Join Date: Dec 2005
Location: United Kingdom
Re: engine rattle
Do what JJB motors says first and clean out the solenoid.
If that doesn't do it then it may be that the solenoid is not working altogether, in which case you need to look at the box of relays under the bonnet, as the contacts or connections may be corroded.
I am not 100% sure where they are on the GTV but they may be under the plastic cover behind the passenger side headlamp.