I have a 1989 535i that I have recently acquired and it has a few niggling problems. The most annoying at the moment is that at speeds above approx 90 kph it feels like it is surging. Not so much as a miss but it feels it want to rev higher and thus surging. (Sorry it isn't a competition to see how many time I can say surging lol, but I cant think of a better term. Any ideas as to the possible causes?? Thanks
Damien
Assuming your intake manifold and head gasket seals are not degraded(vacuum leak), I would say timing chain. Here is a list of what you should be fixing and probably haven't yet:
Ours had a something similar due to a failing fuel pump.
I'll see you and raise you. Failed in-tank pump, failing rear pump. It endd up taking out the fuse contacts for the fuel pump fuse before Einstein here figured out what was going on.
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