VW FOX Cuts out at Higher RPM's Lots of work done and results are limited

Hi Scottie!

Hope all is well...

I have another issue that is baffling.

I had the fuel and air filter replaced and had the fuel injection system cleaned up. The Fox was tested for fuel pressure, rechecked the Timing cause a new belt was installed.

After all that the Fox still didn't run like it should as described below. Oh and the coil was replaced or swapped out of a known good running Fox.

I suggested they replace the CTS and they didn't have time so I bought one an replaced it and the Fox ran like it should...or at least I thought it did. It certainly ran better than when it left their shop.


When I get to a certain RPM typically at the upper end of any given gear or if I were to floor it.. the Fox will begin to die/run roughly as if its running out of gas??! One way I've found to get it out of this cycle is I'll slow down and put it into first gear causing the engine to rev a little and it starts to run normally or smooth again. Otherwise it could stall out or just continue to run rough.

Another scenario would be if I get up to about 75 MPH it will cut out acting just like I describe above.

The CTS I'm using is made by Wells Technology and sold by Auto Zone.

Model SU425

2.2-2.8 K Ohms @ 20° c

0.280-0.350 K Ohms @ 80° c