Intermittent vibration in rev range

[e24nut]

My 89 e24 has an intermittent problem with a vibration which feels like the engine drops to 5cylinders very quickly. Tye engine starts drives and idles fine. When you give it some gas and the transmission kicks down a slight vibration and lag as the engine juos into a higher rev range. This usully happensbin the winter months when temoeratures are below 20deg c. Occaisionally the vibration gets much worse feeling like running on 5 cylinders at idle. This happened last southern hemisohere winter (has had an inspection 2) 9 months ago but was not present during the summer months. I did have an electrical problem corrected when the car would not idle and was running very rich at cold startup which was remedied by reseating and cleaning of ingntion related connectors.

The problem will go away as the car is driven and only seems to be after start up and the first half hour ofcoperation.

As it is intermittent it is hard to diagnose and demonstrate. I can only think that it is electrical or fuel injection related.

Any thoughts / solutions appreciated!

[e24nut]

First rime i havent got a response!

[hornhospital]

Something to consider, I had an E30 here 3 years ago that was doing the same thing. Instead of properly diagnosing it I threw money at it, new everything in the ignition system (wires, cap, rotor, plugs, etc), new injectors (OUCH, $$$$). The miss would go away, I'd think it was cured, then it would return. On a whim I took the AFM off my E30 and put it on the headache-inducing E30. Bingo, no miss. The AFM went to Bavarian Restorations for a rebuild. Two weeks and about $180 later it was back. It hasn't missed since, and I bought the car a couple weeks ago (that's the "Hazel-Ann" in my signature). It is in 10X better condition than my '87 325is. Just what I needed, a 7th BMW. (and that purchase was what kept me from flying to Bountiful, UT to buy that $1300 E24).

[e24nut]

Thanks ken.

I had some problems with the afm a few months ago when the engine would intermittently atop idling and ran really rich on startup. a cleanup and reseat of the electronic connections fixed the problem. The afm xould be the culprit.

Nut