Yes, it is a hall effect sensor.

It takes 25 seconds with out a signal to trip the code. Then the computer doubles the injection and ignition pulses, there is no intermittant code choice.

Assuming that the sensor has never been replaced that would be the most likely cause but I would check the connection for a tight corrosion free fit first. See if that cures it, and then move on to replacement. I ended up replacing mine at around 200K miles. I do remember cleaning that connection about a year or two before replacement, maybe the pulse gets a little weak with age until it cannot overcome and corrosion, so cleaning the connection only delayed the end of the sensor.

It is not hard to replace, getting the old one out is the biggest challenge, the replacement has a little looser fit. The two torx bolts can cause a headache though, make sure you use a quality tool, not one from a cheap kit, if the head strips out then a 30 minute job is going to take hours.

DanR 94 964 241,000 miles*
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DanR