Engine problems on S3-Turbo

[pol]

Hello,

I'm driving a '94 Thema Turbo 16V for about 20.000 Kms with no major problems.

During the past few days the ecu-warning light sometimes comes on while driving (engine warm or warming up) and at the same time the engine seems to lose power. It's like it gets less fuel or bad iginition, but it keeps on running.
After a few seconds everything seems normal again and the light goes out a bit later.
When this occurs during idle, the engine runs too slow and even stops, but it can be started again.

I believe the knocking-sensor can cut the fuel and/or ignition, so i'm trying to check this one.

The 'pedal-to-the-floor-five-times-trick' doesn't work, neither did it work on my previous '92 Turbo (maybe i'm doing it all wrong).

If you think you can help me finding the cause of my problem, please do.

Thank's in advance.

Regards,
Pol