So I followed the ECU Reset procedure and then learning Accelerator Pedal Released Position Learning, Throttle Valve Closed Position Learning, and Idle Air Volume Learning procedures. After all that, CEL light is cleared and the car idles better @ about 950rpm . Can't get it down to 650-700 rpm where it should be though. CEL keeps coming back though after driving for a while. So looking for other ways to resolve this without having to go to the dealer.

 

I wish I could help, but I don't have any idea what is going on. Since the throttle body is pretty sensitive part, do you think you've damage the butterfly in the throttle body? Also, when you changed you spark plugs, did you pull off any tubes that go in to your plenum? If start a new thread on your problem or do some research, it might help you solve your problem.

 

I did move the butterfly just to get in there to clean it so it's possible that may have damaged it, and I also removed a hose to the plenum during the spark plug changed but I connected it back afterward. Anyway, I appreciate all your help.

 

Well like I said, if you had disconnected the throttle body connector, this might not have happened, I am not quite sure if you have damage the throttle body or not, but it could be, because they are sensitive.

 

Thanks to both of you. Made this simple task that much easier for me. I used the "G Power" NGK's and so far so good. Not the OEM plug but works well indeed. Best platinum plug on a budget mindset, or so it says on the NGK website.

Thanks again.

 

I was able to fix my problem. I just wasn't following the relearning instructions properly. On the Idle Air Volume Learning Procedure, the last step was to turn key over and start the car with 3 seconds of when to CEL stops blinking, I was turning the ignition off before and then starting the car. I finally realized that after weeks of trying.
Now my car is running smoothly and idling at about 650rmp. So happy, cause I was ready to take it the dealer.
Thanks for all your help EvilG, and everybody else that help.

 

thanks for the DIY! it seems really helpful because i am going to change mine in the coming month or soon. I need to get a torque wrench though.

 

I couldn't wait for my usual mechanic to replace spark plug so I did it my self.
It was quite an ordeal.
Spark plug oem from autozone. I checked label of all 6 box.
Driver side not so bad to replace. Half way through, I decided to compare gap and dimension of old and new plug. Old and new plug size didn't match--really upset. Autozone gave me two wrong plugs inside box With correct label. The number is the same, only the last letter is f instead of the correct a. I was fortunate to check on the 2nd wrong plug.
Double check and triple check when you tackle this DIY.
After that, car start idle roughy for 5minutes. Then every thing was back to normal
Just in time for dinner

 

Hey guys ..... I'm about to change spark plugs, and have decided to give Denso (IKH16 Iridium Power Performance) a try .....
so, my question is, should I change the Coil Wires as well, and what are some quality wires (MSD, ACCEL, etc)?

 

Changed my plugs yesterday w/ battery disconnected. All went fine, and I decided to spray some TB cleaner in while I had access to TB, which I'm seeing now may have been a mistake. Anyway, put everything back together, and per suggestions here, I did the ECU reset before driving. Idle was a little high at first, but felt kind of rough. I went for a short drive, and G felt sluggish, and idled very rough at stops, but around 700rpm. Got back home, and while parked, gave it a little gas, and it did not want to go over 2300rpm at all. Any suggestions?
2004 AT Sedan, 98k miles if it makes a difference.

 

Forgot to add that the CEL flashed a few times while driving, and came on steady one I got back from a relatively short trip.

 

Thanks for the DIY. Did my plugs yesterday and was very straight forward. Passenger side was difficult to access but was able to get it done. I had oil on the rear passenger and the rear driver side plug, but sounds like its a common thing. Just wanted to note to be careful when tightening the screws that hold the electrical wiring harness in place, I had one of the heads break off the bolt. Didn't get any CEL after the change. I did notice the car drove alot better after though.

 

No coil wires, our cars use coil packs. Denso plugs are fine, I just installed them in my FX.

FWIW, this DIY is very clear. I have an AWD FX and the only difference was I have an extra wiring harness to work around. Other than that, spot on.

 

To update, took G to a local shop this morning, and they determined right away my plug #6 was not connected all the way. Wish I had a code reader to have caught that myself, but I'm told all is back to good now.

 

Stupid question, sorry, but I changed my spark plugs before I found this (very helpful) DIY guide....what if I didn't disconnect the battery before doing all this? Could I have done any damage?