Running Rich solved, finally.
My 3.9 CFI EB has been doing the typical running rich - black exhaust all over the back of the car for almost a year. Everything I tried made a slight improvement - fuel, plugs, plug gap, leads, new O2 sensor etc etc. Last time I had the injectors cleaned professionally. My mechanic at the time said the spray pattern was now much better. But still it ran too rich. My mechanic phoned me last week and told me that they had had a similar problem with another car the same as mine and went to new injectors after trying everything. Problem solved he said and that his company were not going to clean injectors ever again (at least for a CFI).
Seems the cleaned injectors had a better looking spray but were still letting in too much fuel. Anyhow, he installed new injectors for me today (no charge for the labour) and bingo, it's fixed. I am a happy camper.
rev@IRC. EB 3.9 auto. VDO head unit, Focal and Sony speakers, tinted, mags, pacemakers, hi-flow cat, 2.5 inch exhaust, K&N, slotted.