I have a Mk1 1997 1.8 with an M45 supercharger fitted, along with air/water intercooler, crank overlay, Mk2 injectors and an emanage blue. Just lately my car seems to have developed an idle problem, where the idle bounces from 850 RPM upto 1500-2000 and then down again. The car seems to accelerate fine and is without issues, once its warmed up the idle settles down.

I have reset my base idle and checked for fault codes and nothing is showing. I have swapped the MAF over, changed the plugs and coil pack, engine coolant temperature sensor and the issue is still there. What else should I look at?