Also make sure that the rubber bung that cover the inspection port on the backing plate of the drum is still there ... idiots, I mean, brake and tyre people have been known to throw that away, which leads to water ingress.
It's your vehicle and all, but remember that lift kits -- cheap or otherwise -- can get expensive when you have to replace parts that wear prematurely because of the kit.
Yeah, that's a complex vehicle and without proper direction you can be hanging parts off them until your wallet is flat. Remember what the fault codes were by any chance?
A place to start now short of a scan tool that shows you wheel speeds and ABS activation would be to disconnect the wiring to the ABS pump under the bonnet and see how she drives.
Without a good scan tool or a good graphing DVM you could be hanging parts on your FL for days.
To test amperage draw on a battery you need an amp clamp ... a DVM won't handle that sort of current.
You tale emphasises the importance of checking the basics ... the battery (I always throw a boost pack on no-crank/no-start and crank/no-start vehicles just to be sure), and the powers and grounds.
That's a facelift FL1. I have an 06 TD4 2.0L BMW engine. There's no lambda sensor. The Fl2 has a 2.2L Ford Duratorq engine and didn't appear until 2007. That does have a pre-cat lambda sensor.
Check the turbo solenoid vent filter (looks like an old-school fuel filter). It should be near the top of the engine but can fall down. If that fills with water, you get those symptoms.