hey guys maybe you can help me,

When i rev my car in N, you can hear the roar of my place racing intake, ok when i have the car in D drive and i press the gas, after like 3,000 RPM i hear like a knocking sound, and if i rev highter it gets faster and if i let go it stops, it sounds like sumthing ish hitting my car with like a hammer. also when i am stoped at a red light, my RMP needle drops lower and then back up, and my car jerks a little when stoped, and then sumtimes it ish normal, i have clanged my idle control, i think or thatz waa the dealer said. do you guys have any idead, plz let me know????

 

if your car is jerking a little after stopping that might be because of bad coil packs, especially since you are a 99.