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Re: E30 318i Nagging Engine



part of what you wrote:  " Popping the hood, I notice that all three relays
(fuel pump, idle
speed control, and vacuum advance) are all chattering" has got to be part of
the problem.

A chattering relay means that the circuits powered by the relay are getting
rapidly switched on/off.  You may have enough "surge capacity" in your fuel
system so that fuel won't be affected (aside from accellerated and premature
wear on the pumps) but it could be doing nasty things to any electronic
circuitry (motronic stuff) that would account for the way the car runs.  

I suggest you look at the wiring circuits for your car and trace out the
circuits that provide power to those relay coils.  Because I suspect that the
circuit for power to at least the main and fuel pumps is a simple "battery
through ignition switch through relay coils to ground" arrangement, I'd check
out your battery, engine, chassis grounds and the condition of your ignition
switch as starting points.

Harvey