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Happily expanding the To Do list since 1997
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Discussion Starter · #1 ·
Ever had that kind of thing? I was so sure it was the alternator. Something was dragging on the engine, dropping revs sometimes to stalling, alternator belt kept squealing. But it also had a weird sort of bucking or surging effect driving at light throttle. New battery made no difference. Volts looked okay but surely it was the alternator...

Nope, it was a fractured wire to the throttle position sensor.

Weak ground made the TPS signal noisy. So the MS ECU thought I kept pressing the throttle. So it stopped trying to control the idle and closed the IAC valve. So the revs dropped right down. So the alternator struggled and its belt squealed.

When the wire eventually broke, it wouldn't start at all because the TPS signal went over 100% and the ECU did the flood clear thing and injected no fuel. That was when the penny finally dropped.
 
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