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E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

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Old 04-01-2011, 05:32 PM
rtl1369 rtl1369 is offline
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Location: Stokesdale, North Carolina
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Mein Auto: 2001 530 sport
rough idle after spark plug change

Hi Everyone,

2001 530 sport

I followed the threads on this site and successfully changed my valve cover gasket and re built my vanos seals without a problem. I changed my sparks to bosch brand not NKG. The car started and ran with a rough idle. I drove a little and the service engine light came on. I pulled the battery to re set the computer. No change.

Once warmed up the idle flattens out and the car runs good. When cold the car sounds like it may be missing a little . Any advice on where to begin looking greatly appreciated.


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Old 04-01-2011, 07:58 PM
edjack edjack is offline
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Mein Auto: '97 540i 6 speed
Dis it do this before all the work? If not, something you did caused it.

The spec plug is NGK BKR6EQUP. Try a set.

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Old 04-01-2011, 08:08 PM
Jimmys 530i Jimmys 530i is offline
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Make sure the ground that goes from the coil harness to the valve cover grounding is tight. I have replaced a VCG before and had a misfire only to discover it was a loose ground.
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Old 04-01-2011, 09:16 PM
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WagonTheDog WagonTheDog is offline
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Mein Auto: 2000 528iAT
Rough idle at cold start-up is usually misfire(s). Rebuilding your VANOS may or may not cure such a condition, in my case it did not. I have a '00 M52TU, and while giving my VANOS the Beisan treatment cured such cold start issues as RPM dip/occasional stall/occasional limp mode, it did not eliminate occasional misfires on cold starts. I've been studying the topic extensively, and chances are you have a vacuum leak somewhere. If all your hoses, etc. are good, it could very well be your intake gasket. As those gaskets go bad, when it's cold, it's not able to do it's job properly, but after it warms up, there's sufficient expansion to restore the seal. If this is your problem, the situation will only continue to deteriorate, as it takes warmer and warmer temperatures to keep that gasket functioning.
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Old 04-01-2011, 10:39 PM
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bluebee bluebee is offline
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Originally Posted by Jimmys 530i View Post
Make sure the ground that goes from the coil harness to the valve cover grounding is tight

I'm going to add that to the misfire diagnostic tree:
- How to diagnose a typical BMW E39 engine misfire (1)

So far, after reading over a hundred misfire threads, I've added all that has been suggested, as best I could, so that thread is both complete and consistent.
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Old 04-03-2011, 02:22 AM
smallie smallie is offline
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Mein Auto: 1999 528i
Vacum leak???

Possible vacum leak.....????

There was a volentary recall on my 1999 528i in 2002 for hoses that were no good and caused a condition that you have explained.

Is it possible that during your gasket and vanos repair that a vacum hose may have been disrupted??

Just a thought.

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