Removing and cleaning the TB - Its not necessary to remove the throttle body from the intake to do this as this can be done with the unit installed. Cleaning ...

Its not necessary to remove the throttle body from the intake to do this as this can be done with the unit installed. Cleaning the throttle body only affects idle quality as the carbon build up can limit/restrict the air the flows past a CLOSED throttle (idle position). The engine ECU will adapt and compensate for this slow build up (by either slightly leaving the throttle plate a few thousandths of an inch more open at idle **for throttle by wire systems**- or by opening the idle speed controller a bit) so in most cases- the carbon build up won't pose any symptoms or problems and idle quality will remain stable. The only time it will show symptoms is if the battery dies or is disconnected and the ECU adaptation is lost. Once the adaptation is lost- the throttle plate ( or idle speed control motor) will go back to its default programmed closed position and the offending carbon build up will simply choke out the engine causing a rough idle or even stall out. It is important to disconnect the battery when performing this service because if the throttle body is cleaned and the adapted idle memory is not erased- the compensated idle position of the throttle plate or idle speed control will result in a higher than normal idle speed. This will not pose any real harm as the engine ECU will eventually adapt and "learn" to lower the idle speed over time- but until it relearns, shifting the transmission into drive or reverse can result in a harsh engagement due to the increased idle speed.
Anyone that thinks they suddenly picked up some lost power by doing this is suffering from the placebo effect.

Mostly good points, Joel. All I can add is to say I like placebo's. It's all I got, since they do random drug testing at work!

For as easy as this is to do, and for the opportunity to keep my truck squeaky clean inside and out, it's worth it to me. I was never saying it had to be done...just how it is done if you want to do it. As far as doing it while it's on the vehicle -- no thanks. I really don't want that spray going into gosh-knows-where in my engine, not to mention all the carbon that is being washed in there with it. Better to remove the TB, get it clean, and reinstall.

My post wasn't meant to be directed to you- it was more for general information for those that read the thread that might be reading it as a means of fixing an idle or stalling issue. Everything I said in my post is 100% accurate, however i do apologize if i made it seem like it was a rebuttal to your initial post.

Joel

No apologies needed...all opinions are welcome!

Joel

My 2008 is idling VERY high after cleaning TB and Mass Air as you stated in your post. 3000RPM at start and 1500 to 2000RPM in gear. I called the dealer and they said they would hook it to the computer for $97 to "relearn" the idle setting. They did say it could eventually learn it without the computer, but how long does it take? It's going to burn my break pads out if it keeps up too long.

If you hadn't done so already, you can try disconnecting the battery so that the ECU's idle adaptation memory will erase and revert back to its base idle settings.

Joel

I've tried that 5 or 6 times now. When the brakes are applied or the car sits in park for a couple of seconds the engine idle will drop to normal level. Once you let your foot off the break while in gear, and don't touch the gas, it will stay at normal idle level for about 5 seconds then it revs up to 1500 to 2000RPM. I tried it on the street and it actually jumped into 2nd gear and might have made it to 3rd without me ever touching the gas. Do you think I messed up the TB or MAF?

I would do this:
Disconnect the battery. Then step on the brakes a few times. Stepping on the brakes may not do anything, but I heard somewhere that it's a way to drain any remaining electricity from the system. I don't know if it matters or not, but it won't hurt to do it.
Then, go back over all of your connections, bolts, etc. Make sure everything is clean, tight, and connected. I think it's possible that something got missed, or you bumped another connector, or something.
After reconnecting the battery, start it and let it idle for a few minutes until you drive.

Good Luck!

Yes- i would definitely recheck your work making sure you left nothing disconnected or that there are no vacuum leaks whatsoever. I would focus more on the throttle body itself rather than the airflow sensor. A damaged airflow sensor can cause some weird symptoms to occur (excessive lean or rich mixtures) but for your engine idle speed to be bumped up like that- there will have to be an actual addition of air into the intake somehow ( by leak, or by the ECU holding the throttle slightly more open as adapted overtime due to carbon buildup). Note that you may leave the battery disconnected for an extended amount of time for all capacitors to discharge. Good luck!

Hit the ECU with a hammer! We'll teach that little bugger!