Possible fix for idle shudder. Ok, I've taken the car to the dealer and they said there was nothing wrong with it, even though i had the guy sit in it while it was doing it. I kinda figured that what he would say. So, last night I went to a mechanic i know that has one of those fancy computers and hooked it up to the car. while sitting there at idle in drive, under cylinder miss on the computer. the number 2 cylinder misses a few times every cycle on the reader. The other cylinders are fine. The reason the miss doesn't trip the car's awareness system to turn the check engine light, is because it doesn't miss enough times per cycle. So, you may have the same prob, but might not be the same cylinder.