questions bout 02 Cavalier

i bought an 02 cavalier in may...I had the brakes changed the front wheel baring changed and the oil changed...I noticed recently when i turn my ac on the car idles up from 500 to 1200rpms when sitting at a traffic light or stop sign it will jerk you forward. I had been told that i have had smoke coming out my tailpipe.. I had my mechanic to check it out and he said the car didn't idle like that with him...He then told me i must have gotten a bad tank of gas...the car still idles up and down. I don't know about the smoke...

I am in the process of changing my stereo. I had bought and installation kit but forgot the wiring harness. I went to radio shack and i was told that i would have to pay 70 bucks for some interface kit thing. They said there was no other way to wire the new stereo to the newer GM vehicles without it. I was wondering if they might just have tried to sell me something or were they telling the truth?

My engine when it changes gears it makes a clicking noise like its blowing off air...anyone know what that could be?

i'm not sure about your idle problem. but i do know radio shack is bullshitting you. i have a 2002 cavi and i have a aftermarket deck, all you need is the right wiring harness it cost me i think 35 at walmart for the wiring harness and all parts. but doing it this way your factory chimes won't work when door is open or lights are left on and headlights are always on when car is running. now if you want to still have the door chimes you have to buy the interface kit. i personally don't care about the chimes or my headlights on all the time when car is running, but you might it's up to you. oh ya if you want to just get the wiring harness and parts go walmart.

i've been reading other threads and pretty much figured out the question to my stereo situation...

I think that the clicking noise is because i was told that i have blow-off valves but what is the purpose of them on a car with no turbo?
And i still don't know what could have been causing that my car to idle up and down

i have the daytime headlights so no matter what my headlights are always on when my car is running

my 02 cavi never had daytime running lights till i changed the radio.

I thought all cavaliers 00 and up had the daytime running lights. not sure about the 03-04. Weird that your's didnt. sure you just didn't notice it? They only come on when the car is in gear. They turn off in park or if the e-brake is on.

maybe it did and i just never noticed it i'm not sure