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Intermittent rough idle and engine shaking?

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RyanB88
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Intermittent rough idle and engine shaking?

Post by RyanB88 » Sat Aug 12, 2017 12:56 pm

Hi

2006 N52 on 102k miles

Just replaced the CCV and both vanos solenoids to rule them out

Symptoms - the idle on cold can be rough in that it doesn't sit still and constantly hunts up and down the rev range. Sometimes does this when warm but more so when cold

Every now and then on idle the engine will actually shake side to side for a few seconds, then settle down again

No fault codes at all

No loss of performance that I can detect. Still pulls very well

Any ideas what to try next?
Z4 now sold :(

Current - M235i :thumbsup:

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alekos911
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Intermittent rough idle and engine shaking?

Post by alekos911 » Sat Aug 12, 2017 1:19 pm

How about a small intake leak, or a faulty coil pack? These two regularly come up as potential causes for rough idle.
Thank God who created man to create these cars :-)
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RyanB88
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Intermittent rough idle and engine shaking?

Post by RyanB88 » Tue Aug 15, 2017 9:20 am

To add to the above problem

Intermittently when warm, but when cold, it has now developed an annoying jerkiness at low revs! I'm sure it'll be connected?
Z4 now sold :(

Current - M235i :thumbsup:

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ph001
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Intermittent rough idle and engine shaking?

Post by ph001 » Tue Aug 15, 2017 5:49 pm

I'd defo be looking at coils first too. You would certainly need to rule them out one way or another.
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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Poltergeist1966
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Intermittent rough idle and engine shaking?

Post by Poltergeist1966 » Tue Aug 15, 2017 8:40 pm

Had similar problems with a Audi TT - changed all the coil packs and as good as new.
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RyanB88
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Intermittent rough idle and engine shaking?

Post by RyanB88 » Wed Aug 16, 2017 5:57 pm

Hmm might be a good place to turn to. Would they not throw a fault code though if it was the coils?

Today I accelerated in trAffic from first to second gear at around 2000rpm, when changing into 2nd gear the car vibrated and jerked a lot, with it bouncing backwards and forwards. Almost like a dodgy gear change (but not!)

It's quite embarrassing now for any passengers so I hve to get this sorted asap! Thinking plugs and coils next...
Z4 now sold :(

Current - M235i :thumbsup:

z4all
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Intermittent rough idle and engine shaking?

Post by z4all » Sun Aug 20, 2017 9:01 pm

yeh would expect coils to throw up an error. your scanner is good enough to pick that up right?

RyanB88
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Intermittent rough idle and engine shaking?

Post by RyanB88 » Sun Aug 20, 2017 9:47 pm

It's Carly, so is considered one of the best

Jerkiness is getting worse and worse, the whole car shakes and stutters on some gear changes now at low revs, then clears and drives as normal...
Z4 now sold :(

Current - M235i :thumbsup:

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Flyingfifer
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Intermittent rough idle and engine shaking?

Post by Flyingfifer » Mon Aug 21, 2017 1:57 pm

+1 on the coil packs, possibly sparks as well
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Intermittent rough idle and engine shaking?

Post by Maniac » Mon Aug 21, 2017 5:22 pm

Something in the air? (Or fuel) as the saying goes.

My 35i has been rough since the last tank of fuel, only when cold, slight misfires and jerking for around a min or two until it starts to warm up.

Holding fire until a fault develops otherwise I'll waste £99 on a diagnosis that will come back as 'fine when we drove it'

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ph001
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Intermittent rough idle and engine shaking?

Post by ph001 » Tue Aug 22, 2017 9:37 am

Your 35i will almost certainly be the piezo injectors leaking unfortunately. It's quite common not to a get a fault code as well.

OP - just change all the coils. At 100k+ miles they almost become a service item anyway. Worn plugs tends to be misfire under full load acceleration (unless it's a cracked insulator).
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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