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<E28> poor driveability

Dear digesters,
I know that there are technical types (witness the recent column in the
ROUNDEL talking about digest participation) who have far more knowledge
of my auto than I ever will. I am therefore asking for assistance in
diagnosing driveability problems in my '86 535i.
First, let me tell you that I had one of those weird situations caused
by an erratic ECU ( my thanks to Peter Langenwalter) that messed up the
car for weeks. All it would do is run rich and foul plugs. After
replacing both the cat, O2 sensor AND the ECU we at least have it
running.
But it doesn't run well. It starts in the morning, yet it stumbles badly
off-idle for the first move off from rest, and for a few minutes
therafter. It has no power moving away from a light - Camry's beat me
away from intersections. Between 2200 and 3000 rpm it feels arthritic -
stumbling, surging, hesitation. The only way this car runs well, if you
can call it that, is if my foot is planted firmly in the firewall.
Admittedly, that's a fine way to drive, but not conducive to a)
retaining one's license or b) motoring around in our child-clogged
neighborhoods. Oh and yes, mileage is off...if I'm not using the
highway, it's averaging in the high 16's.

We have checked and or replaced the following: Both temp sensors, fuel
pressure regulator, ECU, O2 sensor, idle air stabilizer valve, plugs,
distributor, rotor, and air filter.

I have not replaced, and have not tested, the AFM or the injectors.
Also, the TPS seems to be original, and it does test on a meter
properly. I have not had the valves adjusted in recent memory, or for at
least a year...

I have been told by another tech that these cars had injector problems
that could be causing these symptoms, but alas he no longer works on
BMW's (something about their owners being a pain in the ass!)

Can anyone give me any assistance on this?

And my last question - if I take it to a dealer, do they have a
diagnostic ability that independent shops don't? Would a dealer be
better equipped to help straighten this problem out?

Please reply either here, as a general posting, or to me privately.

Thanks in advance,

Rick

'86 535i
'79 528i
BMW CCA # 148171

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