Auto Parts: car repair/parts, engine acts, k n air filter

Question
hi i am the owner of a 1996 MANUAL Hyundai Accent LS.i recently got my car tuned and a non-disposable performance K&N air filter installed. i also got 4 platinum tip spark plugs installed on standard plug wires.the problem is sometimes when i push in my clutch early and come to a stop,the engine acts/sounds like how it would if i came to a stop suddenly and barely got in the clutch (like if it would cut out).please help!  

Answer
This sounds like one of you plugs isnt firing. Start your engine and listen to it idle. Does it idle rough?? When replacing plugs did you make sure all where firing? You can do this buy starting car and let it idle then remove each wire one by one , listen for engine misfire on each plug...this way you can hear and can tell which plug is misfiring! OR which wire might be bad.  NOW heres the thing also..are you running your A/C when this happens? if so try turning off A/C and see if it still does this. Your A/C puts extra LAG on your car so if your car doesnt have a good spark it will sometime cause engine to feel like it wants to die. Try change out your wires and check you A/C components. Let me know how things go.