[SalvadorP]

I have a similar issue on my 940. Idle swings between 800 and 900, looking like a rythmic misfire.

I have done this:
Compression test (good results)
Replaced plugs
Replaced leads
Sound checked injectors, they are firing properly.
Cleaned Distributor
Cleaned and tested idle valve
Cleaned and tested MAF
Tested for leak with carb cleaner, couldn't find any
Smoke tested for leak, couldn't find any
Replaced all vaccum hoses
Tested for vaccum leak with a leak gauge (there was no vaccum leak neither before or after replacing hoses)

I'm waiting on parts to refurbish the injectors. If Injectors are good and spray partern is fine... Well, then I guess I'm finally using that one grenade my pops brought back from the colonial war.

jk, if it's not injectors I have to assume it's MAF, O2 sensor or less likely idle valve. I would rule out the distributor because the injectors are firing steadily.
Hope this helps. I've been chasing that bad idle for 2 years now...