Rough idle issue....

Edward · 08-25-2011, 04:19 PM

So twice now on cold starts, my car (16k miles on odometer) would fire up fast, and as the rpm settles at 1100 and continues on down to the 650-700 mark, the car would vibrate faintly. When I would rev it, it revs fine and it also drives fine, however it would go back to a rougher low idle.
After shutting off and turning it back on, it would be a normal smooth idle. No check engine lights or any other fault lights register either.
I've never had a long crank or any engine problems. Is it a fluke? or do I have a bad injector or something?

AddictedToBavarian · 08-25-2011, 04:21 PM

I would say if it continuously happens it may be an issue with the fuel injectors. I would give it a few more days of paying close attention to cold starts. I had a bad fuel injector on my other vehicle and it was VERY noticeable.

mofbb · 08-25-2011, 04:35 PM

I think it happens on every 335i

EngineCo52 · 08-25-2011, 04:40 PM

happens on mine, bmw told me poss vacume leak somewhere

matrix76 · 08-25-2011, 04:50 PM

Had the same problem, but not a 335i, and it turned out to be a software update that the dealer did in June and it's been great ever since. Mine was quite bad at times.

JunkStory · 08-25-2011, 04:50 PM

So many possibilities:

1) HPFP
2) Injectors
3) Spark plugs
4) Coils
5) Sensors
6) Vacuum leak

PKizzle · 08-25-2011, 05:15 PM

I've felt this on and off in my 335is...w...800 miles. A mild flutter when the rpm hovers between 600 and 700 rpm. With the AC on it idles a bit higher around 800 rpm and doesn't seem to do it then. My 09 335i used to do the same..even after the HPFP recall.

Peertwelve · 08-25-2011, 06:06 PM

Quote:

Originally Posted by Edward

So twice now on cold starts, my car (16k miles on odometer) would fire up fast, and as the rpm settles at 1100 and continues on down to the 650-700 mark, the car would vibrate faintly.
After shutting off and turning it back on, it would be a normal smooth idle. No check engine lights or any other fault lights register either.
I've never had a long crank or any engine problems. Is it a fluke? or do I have a bad injector or something?

this happens to my 08 335 before and after replacing HPFP and four injectors. Bad gas maybe?

08-25-2011, 04:19 PM	#1
Edward Colonel 377 Rep 2,982 Posts Drives: 2013.9999 E92 Jerez ZCP Join Date: May 2010 Location: Los Angeles iTrader: (2)	Rough idle issue.... So twice now on cold starts, my car (16k miles on odometer) would fire up fast, and as the rpm settles at 1100 and continues on down to the 650-700 mark, the car would vibrate faintly. When I would rev it, it revs fine and it also drives fine, however it would go back to a rougher low idle. After shutting off and turning it back on, it would be a normal smooth idle. No check engine lights or any other fault lights register either. I've never had a long crank or any engine problems. Is it a fluke? or do I have a bad injector or something?
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08-25-2011, 04:21 PM	#2
AddictedToBavarian My other ride is a Bianchi Infinito 96 Rep 2,767 Posts Drives: Miss my E92 but love my E46 M3 Join Date: Apr 2011 Location: North Jersey iTrader: (2)	I would say if it continuously happens it may be an issue with the fuel injectors. I would give it a few more days of paying close attention to cold starts. I had a bad fuel injector on my other vehicle and it was VERY noticeable.
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08-25-2011, 04:35 PM	#3
mofbb Lieutenant 37 Rep 517 Posts Drives: '13 E92 M3 Join Date: Oct 2010 Location: British Columbia iTrader: (0)	I think it happens on every 335i __________________ 335i Cabriolet Jet Black/Coral Red - Retired but will never be forgotten M3 Coupé DCT Competition Package Mineral White/Fox Red E9X Picture Game: 2 points (Slow sign, Leaves)
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08-25-2011, 04:40 PM	#4
EngineCo52 Major 60 Rep 1,457 Posts Drives: 2007 Montego 328xi CPE Join Date: May 2011 Location: Havre de Grace, MD iTrader: (2)	happens on mine, bmw told me poss vacume leak somewhere __________________ E92 328xi Mods-KW V1-BMW Performance Exhaust-Matte Black Grill-CF Mirror Covers-CF B-Pillars-20% Tint-Coming soon:AG M310's, M3 Rep Front, Black Roof, Vinyl Window Trim E9x Picture Game-8 Points-Roundabout, Something Remarkable(stack of 50 g's), Cruise Memorabilia, Dirt Road w/ Trees, Michael Jackson, Police Station ,Dress-Up Funny, TPMS
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08-25-2011, 04:50 PM	#5
matrix76 Major 61 Rep 1,300 Posts Drives: 2020 Z4 M40i Black/Red Join Date: Sep 2009 Location: Port Dover, Ontario iTrader: (1)	Had the same problem, but not a 335i, and it turned out to be a software update that the dealer did in June and it's been great ever since. Mine was quite bad at times. __________________ Brian Black Sapphire, Black w/Burrwood Trim & Shifter, 162's, Mtec H8 AE's, DS1 HID 6000K
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08-25-2011, 04:50 PM	#6
JunkStory Major 160 Rep 1,307 Posts Drives: E92 M3, 8V RS3 Join Date: May 2008 Location: 98230 iTrader: (3)	So many possibilities: 1) HPFP 2) Injectors 3) Spark plugs 4) Coils 5) Sensors 6) Vacuum leak
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08-25-2011, 05:15 PM	#7
PKizzle Second Lieutenant 153 Rep 291 Posts Drives: F80 M3, E36 M3, X4 M40 Join Date: Jun 2011 Location: Cary, NC iTrader: (0)	I've felt this on and off in my 335is...w...800 miles. A mild flutter when the rpm hovers between 600 and 700 rpm. With the AC on it idles a bit higher around 800 rpm and doesn't seem to do it then. My 09 335i used to do the same..even after the HPFP recall.
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