idle speed control minor problem

[rares]

hi there
I do have a E53 4.6is and and w/ engine at idle in parking ,everytime I step on gas pedal up to 2-3000/rpm and then let the engine come back to idle speed (6-700 rpm or whatever)....it goes under to much almost to die for one second and then it comes back to normal ,it doesnt come back from higher rpm back to 6-700rpm smoth like it should.For those who know the tech of this engine M62 could u tell me who controls this rev , I do have a new EDK ,new spark plugs, new ign coils .THANK YOU

[Denis0331]

how about air filter maybee air and fuel mix ration is off, or if filter is good check the intake box and tubes make sure there is no cracks....also check out some fuel additives to clean your fuel injectors...thats the cheapest thing you can do ...another thing is u can take it somewhere to get your sensors checked.

[rares]

Thank u Denis
Everything checked and fine unless there is a vacuum or sensor that is not doing the job and let's the ECU to figure out how to keep the idle at stable point.Dont know and what's worst is that not even the dealer doesn't know and everybody will start guessing and Me paying.Happened before ......maybe better luck w guessing this time (monday take it to dealer again)

[romeokc10]

Did you ever find out what was causing the problem, mine does it also, especially after running the AC before shutdown. On the next start it will rev up and almost or sometimes die.

[rares]

Nope.... Problem still there. So in order to keep the idle speed up , where it should b, I drive in sport mode in town ( a lot of stops and go) and normal on highway. Now that the summer in here , The AC on helps also to keep the rev up . I just don't want to replace the transfer case again.

[BigBlack48is]

Originally Posted by rares

Nope.... Problem still there. So in order to keep the idle speed up , where it should b, I drive in sport mode in town ( a lot of stops and go) and normal on highway. Now that the summer in here , The AC on helps also to keep the rev up . I just don't want to replace the transfer case again.

I don't think driving it in sport mode or having the AC running will cause your transfer case to go boom! not changing the fluid and/or guibo's will cause that... or the +140mph runs on the expressway

I would think you have some kind of vacuum leak or leak in pipe between your MAF and intake. My N62 with the AC off will have a rough idle at times too, I think it's because of the weather ( or at least that's what I tell myself )

Hope you find it!

[bcredliner]

Have you or the dealer checked for fault codes?