K series idles rich ........HELP.

[carphotographer]

'96 K series 1.6 Supersport engine - idles rich
Have a '96 K series 1.6 Supersport that appears to run rich at idle The engine runs an original ECU, but has a head by Minister Racing - different cams, gas flowed head, uprated gasket and verniers.

On the move it seems to be okay but when at idle it seems to be running rich. Spark plugs get sooted up quickly but are dry.

Any ideas.....

[carphotographer]

Thanks for the answers,
Timing has been mentioned by a few people but surely if the timing was out at idle it would be out throughout the rev range :-/

[carphotographer]

11. days later since posting and it's still not fixed

[carphotographer]

ran okay for 15 years with this set up :-/