Brand new to this so be patient please!

[IAN 320]

5 years of BMW ownership having first bought a Jap import 318 Sedan with low Km's and in really great condition for its age being an 89 model. Really happy with that car to the extent that I've kept it in the family.
We now own a 1991/2 320I E36 (non vanos). Its only done 138000 K's and this I think might contribute to some of the problems experienced presently.
It goes but its erratic to say the least. I am past the point of selling it (as it certianly has potential to be a nice car) but, presently frustrating to find the problem(s).
It idles up and down or hunts. It has a flat spot (sometimes). I have had it with 2 supposed experts. Coils replaced, MAS checked, Injectors cleaned, plugs replaced, and of course the dreaded ICV cleaned and I think I'm going to have to do this again (myself).
I have bought the Bently manual so I'm definately on to a good start!
Looking at this web community I am hoping to gain some further knowledge.
This car is a 19 YO absolutely original and pristene vehicle.
I think it has great potential and I am willing to persevere.
I'll post pics of it if I don't burn it!