Rough Idle

[SE1957]

I have a 2008 Toyota Camry SE with the 2.4 engine and auto trans. If I'm stopped and in drive the engine feels as if it's going to stall, the entire car "shutters". The tach reads between 700 & 800 but if I place the gear selector into either neutral or park it becomes "glass" smooth, I even have to look at the tach to see if the engine is still running! In neutral or park the tach still reads 700-800 rpm and the A/C is always switched off.
I've had it to 2 different Toyota dealers and yesterday to my regular mechanic. 1st dealer said to disconnect the battery and bring everything back to default positions...no difference, battery was off for 35 minutes. 2nd dealer said to have the throttle body cleaned, which I did...no difference. A bit of background with the vehicle, I've had it since new, I drive 170 hiway miles per day, I use Shell branded fuel, oilchanges always at 5,000 miles, dealer serviced since new.
So yesterday my mechanic checked everything, engine mounts (OK), any error codes (none) cylinder compression (all within spec) spark plugs (OK except for 1 so I asked him to change them all), he installed 4 NGK iridium plugs and guess what...it still shutters & vibrates!!
Anyone out there have any suggestions?

[leakyseals]

I have it too in a 02 I4. Its a hard one. A hand over the exhaust when its warm feels like a skip. It seems as if the electronic throttle body does not compensate for load as it should (fans, a/c, going into drive, etc.) Repeated TB cleaning (and the small visible hole inside) has helped. What also helped was the use of synthetic oil (mobil 1 HM 5w-30). I have read that a lazy upstream AF/o2 sensor can cause rough idle and skipping without triggering a failure CEL. I need a new manifold cat before next inspection, and plan to replace the upstream af/o2 denso sensor along with it. That Denso AF/o2 sensor can be had for about $100. Its the one visible when the hood is open, top/middle of the front cat, long wire with a clamp on the water hose.

[Nums]

How long has it been since you disconnected the battery? Your car needs a bit of time in order to figure things out again. I know my car gets a rough idle for a week a or two after I disconnect the battery for a while.

[leakyseals]

Originally Posted by Nums

How long has it been since you disconnected the battery? Your car needs a bit of time in order to figure things out again. I know my car gets a rough idle for a week a or two after I disconnect the battery for a while.

Thats way too long, if things are right this should not happen. The longer calibration takes, the farther from factory spec you are. Means you need a tuneup, TB/Maf cleaning, injector cleaner, etc.