WTF, it seems to get worse and worse or it might be me just looking out for things. Ive been shakey at idle for quite some time now and it only shakes when the AC is on and im in park or on brake (im an auto btw). i dont know what it could be. I told them at the dealership a while back and of course they didnt fix it right. On the paper i signed when i got the car back it says they replaced the throttle body and something else? when i turn the AC off, it stops? Its too damn hot down here to have the AC off. Just wanted to know if anyone else has the same problem or it could also be my exhaust? Although everthing is on correct? Let me know!

 

my guess is the alternator, i think the AC draws its power form there, not sure though just my guess

 

yup.

 

The AC compressor puts a lot more load on the engine that what the alternator is. You will even notice a power difference with the AC on. When the AC clutch engages and the compressor starts to spin, it places a good load on the engine (compressor is being turned by the belt off the crankshaft) , making it idle rougher. The ECU kicks up the idle to compensate, but on some smaller motors it will still idle a bit rougher. You will notice that when the compressor cycles back off it will smooth out more, then act that way again when the compressor cycles back on.

The clutch on the compressor does draw a small amount of electrical power, but it isn't that load on the alternator that you are feeling.

If it is excessively bad, then you may have another running problem, and this effect is just making it more noticeable.