I recently took my car to a mechanic in my area, and got the ignition coil/spark plugs replaced, due to a shaking/shuddering while accelerating. After the work, the acceleration problems stopped, but a faint shaking I had continued. It has steadily gotten worse, and I?ve taken it back to the repair shop (STS) and been told that they can?t find anything wrong with it. I?m tempted to take it to another mechanic, possibly at a dealership, and have it looked at again, but I?d like to get some insight as to whats wrong if possible. The shaking gets worse after the car has been running, usually after 5-10 minutes when the car has warmed up. It only really shakes when idle (at lights or stop signs), though I think I can feel it slightly when driving. Shifting from anything in gear to parked makes the shaking stop, or at least become a great deal less noticable.
I am fairly clueless when it comes to cars, so if there is any other questions you can ask me to maybe narrow it down, feel free to do so. Thanks for your help!