I have had the CEL and VSC lights come up a few times on my Wife's RX350 a few times. The first time I took it to the stealer, and they charged me $80 to clear it and tell me that it wasn't covered under engine warranty, and sometimes they just pop up for no reason.
So this time I used a reader ( available for $80 ) and read code P0354, Ign coil D. With a little googling, I found that D is the front center coil.
Ordered coil online for $45.
Now the best part, the how to:
1) Pop hood and remove engine cover. You simply grab on to it and pull it up. It just pops off.
2) Remove new part from box, so you know what you're looking for.
3) Locate problem coil.
4) Use 10mm socket to remove the only bolt on the coil.
5) remove wiring connection.
6) replace with new part.
I was having the same issues as op and found different scenarios on the internet regarding fixes. This was probably the best described effort (especially with the pic...which was a huge help in doing this fix). Thanks a ton to the op!
So...for anyone else who might stumble across this with similar problems...
2007 Lexus RX-350
Symptom: Check Engine and VSC lights lit up (constant). First noticed that there was an odd shaking of the car when driving 60-70 mph. No other problems upon first noticing this shaking. After driving the car for a day or so, started noticing the engine a little shaky on starting and the shaking was starting to appear a little more frequently at lower speeds. Also noticed that immediately after the shaking ended, the Check Engine light would start blinking (I'm guessing it was registering a new exception being thrown from the computer).
Fix: Amazon... Beck Arnley 178-8311 Direct Ignition Coil (I was pleasantly surprised to find that when the part arrived, it was OEM...or at least seemed to be, due to the Toyota stamping). The part was extremely easy to remove and replace...maybe with the exception of the connection cable, which clicks onto the ignition coil. I needed a vice clamp to get it to release from the old coil...but once you put enough pressure on it, it releases and slides off easily. After that, just simply unscrew the bolt with the aforementioned 10 mm socket and all is good.