This is a tough one. I'm not sure why the needle sweep and engine shudder are connected.
On cleaning the throttle bodies: For ease and safety don't move the butterfly valve while you are cleaning them. Yes you can get them cleaner by pivoting the valve out of the way, but sometimes this causes idling issues that can't be fixed with the reset procedures. I'm not sure if this is in the thread you linked but some people ended up having to buy whole new throttle bodies.
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some mods
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