Sudden Knock while idling

[saleem JDM VRG]

Saleem here from Trinidad
Well what happens with me is that when the car is in traffic or some thing and idling for app. more than 6 minutes the car starts to give me a sudden jerk like from the front of the car. I had that problem before & i changed plugs and the problem stopped but after app. 5 months the same shit happens.Apart from that now the muffler man was telling me that i`m burning too rich cause the exhaust is burning eyes .What can i do to stop burning so rich?

[Auto-9]

Hmmm...only way I can think of is install smaller fuel injectors to force the car to cut back on fuel, or somehow pump more air into the engine at least to the point where the injectors can't compensate anymore. Either way you're either trying to cut back on fuel or increase the air.