Rough idle after spark plug change

Laserdude · 08-25-2017, 08:34 PM

I know there have been posts about this but u haven't found a solid answer. Got 3 coils and all spark plugs changed. It's been about a month and a half and I've driven about 400 miles. On cold start the engine gets rough when it drops below 1000 rpm. I can feel the car shake and it doesn't sound very good. When i start driving any distance the engine functions smoothly and has full power. Is this something that could be resolved with time/software? Should I worry about this?

Meatos · 08-25-2017, 11:19 PM

Did you change to colder plugs?

dublin14 · 08-25-2017, 11:22 PM

What plugs? Check your coil connections... Go through them all.

CarJunkie · 08-26-2017, 12:02 AM

Have you had any misfires? Rough idle can be a number of things, including HPFP or leaky injectors. I replaced my plugs and coils, reset the LVS adaptations, and still had rough idle, ultimately ended up with new HPFP and injectors.

08-25-2017, 08:34 PM	#1
Laserdude Private 39 Rep 94 Posts Drives: 2007 Jet black e93 335 Join Date: Apr 2016 Location: USA iTrader: (0)	Rough idle after spark plug change I know there have been posts about this but u haven't found a solid answer. Got 3 coils and all spark plugs changed. It's been about a month and a half and I've driven about 400 miles. On cold start the engine gets rough when it drops below 1000 rpm. I can feel the car shake and it doesn't sound very good. When i start driving any distance the engine functions smoothly and has full power. Is this something that could be resolved with time/software? Should I worry about this?
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08-25-2017, 11:19 PM	#2
Meatos Private First Class 59 Rep 146 Posts Drives: 335i n54 -07 Join Date: May 2017 Location: Sweden iTrader: (0)	Did you change to colder plugs?
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08-25-2017, 11:22 PM	#3
dublin14 Banned 148 Rep 388 Posts Drives: Bmw 335i- F150 FX4- Audi A4 Join Date: Apr 2011 Location: Toronto-Canada iTrader: (0)	What plugs? Check your coil connections... Go through them all.
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08-26-2017, 12:02 AM	#4
CarJunkie Colonel 2617 Rep 2,819 Posts Drives: e82 1M, f87 M2cs Join Date: Nov 2011 Location: Tri-Cities, Washington iTrader: (1) Garage List 2020 M2cs [0.00] 2011 BMW 1M [0.00]	Have you had any misfires? Rough idle can be a number of things, including HPFP or leaky injectors. I replaced my plugs and coils, reset the LVS adaptations, and still had rough idle, ultimately ended up with new HPFP and injectors. __________________ 1M track toy mods: BMS chargepipe, BMS OCC, ADE FMIC, ADE motor mounts, MadDad/Lightweight Ti exhaust, ADE custom oil thermostat/cooler, custom MHD tune, F10 550i clutch, Ohlins R+T, Vorschlag camber plates, M3 'vert FSB with Turner endlinks, Stoptech Trophy BBK.
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