E34 525i Flat Spot Problem

["Eugene Hoe" <eugene@xxxxxxxxxxx>]

My E34 525i (M20) has this intermitted surge or flat spot problem.
Ocasionally between 3 - 4000 rpm, the engine experience
a flat spot and when you try to accelerate the engine surges as if there was
air pockets in the fuel line. So basically the
engine hesitates to rev between 3 - 4000 rpm. This problem goes away after
driving for a short while. I can't seem to find
a pattern to when it happens, it just seems to intermittently happen.
Everything seems to be fine, the idle is fine, no flat spots
below 3000 rpm, etc.

Could it be the fuel pressure since it only occurs above 3K RPM?. Any
suggestions/advice welcome. TIA.

Rgds,
Eugene
E34 525i

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