The Alfa 145 floor pan is known to be a rust hotspot. Common areas that suffer are the door sills and around the foot wells.
If you identify that your 145 is suffering from this as with other rust and corrosion problems you'll need to either treat it and try to stop it, or replace the entire floor pan and / or sills.
Another common complaint with the 145 is erratic engine idling, eg the engine feels and sounds like it might stall when it's idling.
This is generally either caused by a faulty or dirty MAF (Mass Air Flow) sensor or a clogged up throttle body.
Depending on your car this could be a DIY fix. To try to improve the engine idling you should start by cleaning the MAF sensor with special cleaning fluid, don't be tempted to use WD40 or something from the kitchen cupboard as you could make the problem worse.
If cleaning the MAF doesn't improve the situation you can try cleaning the throttle body using a suitable cleaner and brush.
If the problem persists after cleaning both of these the next step would probably to try a new MAF sensor and see if that improves it.
Tell us about your 145 problem