More than likely gonna be the ISV matey. Does it seem to drop too low on the revs when your slowing down on the brakes and drop the clutch, sometimes stalling? And is it idleing right? (Bout 800 to 1000rpm) If so take it off and give it a proper spray through with carb cleaner, leave to soak in petrol for a good few hours, repeat the carb cleaner, then a finishing touch with the WD40 caan through it to clean it even more and dry it out!
Def do this BEFORE you even think about adjusting the idle higher! You'll only be over compensating, this will lead to problems later.