Hey everyone im new to the site and i got my first question. When i stop at a light my cars idle can drop as low as bout 550 rpm, NOT 5,500, actually 550, so im wondering what the hell is wrong wit it, i brought it to a shop and he said he fixed it (for free so it doesnt matter) but the idle used to jump up and down betweet 900-2,000 but now it only drops and stays instead of jumping around, any input would be great, thanks!