E30 Drivability Problem (tricky)

["Craig Lovold" <Craig_Lovold@xxxxxxxxxxx>]

Help, my poor car ('87 325i) is sick.

I am currently getting about 6 MPG.  That ain't normal.

It idles like a harley and bucks like a mule under light acceleration.
When pushed past 1/2 way down it smooths out, and when floored it appears
to have full power.  Black smoke is seen exiting the tailpipe especially
when floored after running badly for a while.

Then, like magic, it smooths out and runs fine for a short while.  When it
comes back to life the idle shoots up to about 1700 for a while and then
calms down.  This happened about a month ago for 3-4 days and then
starightened itself out.  Now its back, and the frequency of running right
is down.

The MPG guage reads around 6 MPG except when dropped to idle, then it reads
about 25 going downhill at 60 MPH.  Normally it would peg the needle all
the way left when coasting, so it is burning a lot of fuel even at idle.

And the smell is interesting.  (I assume its the smell of partially
combusted fuel)

I checked the coolant temperature sensor, the O2 sensor, and the air flow
meter is not binding.

The local shop (that I trust) can't get me in for about 2 weeks.  I feel
bad driving it like this.

Does anyone have any good (or even bad) ideas?  I need to take this car on
a 200 mile trip next Tuesday and really want to get it fixed ASAP.

TIA,

Craig Lovold  (craig_lovold@domain.elided)

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