Engine speed sensor problem

[admc6]

I have been having some reving problems, where the rev counter jumps up and down alot. I have had a similar problem in the past where the revs would drop and the car cut out. This problem was sorted, as far as i know. I have had the crank sensor replaced and the hall sender.
This problem happened two times and at the same point in the petrol tank. I was thinking that it might be picking some dirt up from the tank and its affecting the fireing.
Put the car on vag com yesterday and it came up with this:

VIN Number:   
License Plate: Mileage:   
Repair Order:
Control Module Part Number: 037 906 025 R   
Component and/or Version: SIMOS 4S           2104           
Software Coding: 00000             
Work Shop Code: WSC 01269
1 Fault Found:

00513 - Engine Speed Sensor (G28)         
16-10 - Signal Outside Specifications - Intermittent

Readiness: N/A

Where is this sensor?
and
Is it different the the crank sensor thats behind the oil filter?

[leegt5]

The engine speed sensor is the one behind the oil filter !! Also known as the crank sensor !

[AndC]

Best of luck..

Seems to be a fairly common problem that gets progressively worse with these Mk III's!

I ahve the same problem and have replaced the crank sensor, replaced the ECU power relay (No. 30) noew I am saving my pennies to try and sort out a new Hall sender and if that doesn't work I've been advised to try the coil pack!

 Where does it all end??

[admc6]

I have had that one changed once, but it was less than a year ago so will still be under warranty.
I was told at the time that it had a earth fault to it from the ecu, but i'm not sure how true this was, long story.
The mechanic had put a new earth to it it, but that shouldn't affect how it runs, should it?

[admc6]

Does anyone know if eathing a part from a different earth source would cause an intermittent fault?

I wouldnt have thought that personally. If not i will get the engine speed sensor changed again