juddering 3B at 190kmh

[s2carlo]

I need some advice on something that happens on my (MRC-tuned) S2 3b.

I get ampel boost (1.6bar absolut) but between 180 - 200 kmh (in fourth gear) the car hesitates, judders a bit and then puls again till 220kmh where 5th gear needs to be selected.

I would like the hesitation to not appear.
What would suggestions be to look at??

[Greg_S]

could be ignition related and not getting a good enough spark