Hi all

Question(s) if i may
1. When i am driving and turn the aircon on i find that when slowing down or puting the ckutch in the engine speed drops to the point that it sometimes cuts out - what could be the cause
2. When i pull away - sometimes there is a bit of a lag (non-turbo) before the car picks up and catapults forward. Could this be plugs?

I am almost due for 150,000KM service. I was told plugs don't get changed on the service interval. So what could cause point 2?

Thanks in advance.