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Re: Strange hesitation on long drive & Idle



Ron, have you looked into the fuel pump?  Usually this thing begins to
make a humming noise before they go out, but not always.  Your car may
have two pumps, the one in the tank, and one outside the tank.  If
either one goes, you will have similar problems.  If nothing else pans
out, have someone check the fuel pressure to the fuel filter, and if its
ok then check after the filter.  Bear in mind that I dont know your car
intimately, but rather generically (I'm relatively new to BMW, in the
past I owned a GTI for 12 years).  If you have a manual service, it may
point to the simplest way to diagnose the fuel pressure.

Another possibility that comes to mind is the O2 sensor.  I've had one
car behave like yours due to a faulty O2 sensor, and its not necessarily
easy to diagnose the problem.  In other words it may put out a voltage
but may not be the right voltage if its at the end of its life.  If
yours is due for a change, you might just replace it first before you
look at the fuel pressure.   Good luck.  

John - Louisville, CO 
1999 BMW 528iT 

Ron wrote:> 

A few possibilities. 
1.  bad gas from Montreal. 
2.  rain on the trip there, got the wires damp, though that has never 
happened before, and didnt cause any issues yesterday during a downpour 
while I was driving, and only seems to happen after a few hours of
driving 
3. Sticky ICV valve ( been cleaning mine out with Carb Cleaner for a few

months since the last issue of stalling at idle. reason: I am a recently

returned University mature student on a budget) 
4 Dirty fuel filter ( though I think not due to the intermittent issue) 
5 problem with the ignition coil.  Maybe it has an intermittent
problem?? 

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