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Old 20-08-2017, 07:17 AM
4xhausts 4xhausts is offline
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Default Idle issue and lumpy acceleration

Yesterday my car was idling with a slight drop/fluctuation in revs, enough to get a bubbly warble from the exhaust, which then developed into hesitant power delivery when engaging gear and pulling away. Feels similar to a misfire but not as harsh. The symptoms are only there between the idle range and about 1500 rpm, after which the car drives fine, with no hesitant power delivery.

Searching the forum, it's littered with idle issues: vanos, throttle position sensor, spark plugs, air leak etc.

Just wondered if anyone has had this issue as I describe it?

The revs only drop very marginally below usual idle levels (700 odd rpm) and the lumpy power is really only when initially pulling away before flattening out to normal.

Might try disconnecting the TPS later to see if that solves it, as I read that can be a fix/diagnosis.
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Old 20-08-2017, 09:33 AM
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Could be one of many issues as you have mentioned but it would be worth getting the codes checked also worth checking the simple things like the notorious rubber bung that dissolves with age,

http://www.z3mcoupe.com/forum/showthread.php?t=9557
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Last edited by Dave P; 20-08-2017 at 10:02 AM. Reason: typo
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Old 20-08-2017, 09:44 AM
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Looks like the pictures have all gone but here's the link to the part in question,


http://www.realoem.com/bmw/enUS/show...diagId=13_0442

part #5
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Old 20-08-2017, 09:54 AM
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Bung can be seen sitting above alloy engine mount ,

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Old 20-08-2017, 10:38 AM
4xhausts 4xhausts is offline
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Thanks Dave. Coincidentally, I was ordering some parts last week and added the rubber bung to the list having read about it previously. It was about 70p and I had seen the previous threads so thought it worth getting.

Just drove the car this morning having taken the TP sensor off and given it a clean before putting it back on. only did a short drive but seemed ok. Will get it checked this week as it's in for its MOT on Tuesday.
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Old 20-08-2017, 12:47 PM
kwoffa kwoffa is offline
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As the cap can come off quite easily,i put a bolt in the pipe with a small jubilee clip around it,that was about 8 years ago now,still there,i have just had a rough idle sorted out,in my case it was the Solonoid's in the Vanos unit,playing up....sometimes it can be a hose,or the ICV.You just have to go thru a process of ilimination,getting the codes read is a good starting point.
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