High Idle after spark plug replacement

[Bassomatic]

Hello,

 

I have a 2003 LE 4x4 with 204,000 miles. I just replaced the spark plugs with Denso Iridum plugs. The old plugs were not excessively gaped. I think I replaced them at 100K also. Anyway, had the plugs replaced, mechanic cleaned the throttle body as well.

 

Now the SES light is on and it will not idle at less than 1500 rpm when in park or N. When I stop, in drive, like at a light, I see the rpms drop then bounce to almost 2000 then down to 1000 then back to 1500.

 

We thought that the computer needed to relearn...no dice. He reflashed the idle in the ecu, I'm sure that I did not say that correctly, what he did was reflashed the "idle air learn"... is that right. Regardless he reflashed what could be reflashed on the computer to address the problem...no dice either. Still idles way too high.

 

I reset the ecu or ecm by pulleg the neg for 24hrs. SES went out for a bit, seemed to idle ok for a bit, then after a few miles, back to the high idle and ses. Now after doing that, the high idle code is gone (even though it is still idling high) only to be replaced with a lean bank 1 code.

 

UPDATE - spoke with mechanic, says that the reflash is now "taking" and the SES is off and idling low until you stop the truck, then when you restart it, it goes back to idling high and the SES comes back on.

 

ARRH I'm going nuts with this truck!!! Any thoughts! Thanks for the help.

 

-Ty

Edited September 1, 2011 by Bassomatic

[Cuong Nguyen]

Is the throttle/cruise control cable tensioned properly? Check the ignition timing?

[Bassomatic]

I dont believe the cruise works that way, this is a drive-by-wire system, I could be wrong.

[Bassomatic]

i

Edited September 1, 2011 by Bassomatic

[Tungsten]

Wrong heat range? Wrong gap? Try basic dealer plugs?

[Bassomatic]

found this http://forums.maxima.org/5th-generation-maxima-2000-2003/394257-do-not-clean-02-03-thottle-body.html not good

[Bassomatic]

plugs are correct size, it drives just fine.

 

found this http://forums.maxima.org/5th-generation-maxima-2000-2003/394257-do-not-clean-02-03-thottle-body.html I believe the engine is damn close.

Edited September 1, 2011 by Bassomatic

[nunya]

merged your double topics together

 

I'm no r50 person but don't IIRC some people complain about o2 sensors on them going out and causing wHierd running issues

[Bassomatic]

Thanks for the merge (I guess!?), I just wanted to get as many responses as possible.

 

I have been looking all over and it seems that the cleaning of the throttle body, which I did not ask for btw, might be the culprit. "The Internet" says that cleaning a drive-by-wire system TB is a big no no and can cause the ECU to not be able to accept an idle air lean procedure, well it accepts it, it just does not remember it, which is exactly what is happening at the moment.

[Tungsten]

If someone was stupid enough to spray carb cleaner into the throttle body filled with electronic bull@!*% then this is what you get because carb cleaner will strip all coating on whatever is inside. I am not sure if an oxygen sensor malfunction will cause a high idle but anything is possible on a modern engine.