I've recently started having some very odd problems with my 1987 190D 2.5 turbo.
I'd replaced the alternator with a new one a couple of months ago, but within the last month, I've noticed that the headlights and dash lights dim whenever the car is idling.

I figure it's the alternator that needs a new voltage regulator so I'm getting that taken care of tomorrow.
However, last night I started the car and noticed it's idle is far lower than usual, also, my anti lock brake warning light came on and all my gauges went dead for several minutes.
After a couple of minutes the warning light and the gauges came back to life.

I've replaced the fuel filters a few days ago and the engine usually runs OK, but for some reason it's idle sounded really low and quite different from most days.
Could there maybe be some connection between my ongoing electrical problems and engine performance?
Would the malfunctioning alternator account for the dead gauges?

I got the battery checked out at a shop and they said it was good and in working order, but they said it was the wrong battery though (it cranks out 850 cca and is a truck battery so I don't know if it matters or not).

I checked the fuse box and everything looks good.
Is there maybe something else besides the alternator I should be checking on?