Rough idle during slight pedal press

HH1815 · 08-28-2019, 04:30 AM

I have a rough idling at cold start. After a minute is fixes itself however if I slightly feather the gas pedal between roughly 850 -1000 I see my rpm go up a little bit to 1000 then drop down to about 550rpm and the engine starts shaking/idling really rough until I depress the pedal. I initially thought it was the plugs so I changed them to the 97506 .22 gap however its still happening. My next idea is to enable the cold start back to stock setting on the bm3 tune.

I'm n55 ewg w/ do, cp, injen intake, stg1 bm3.

Any ideas on why it might do that? I don't have codes either

Marlinman · 08-28-2019, 05:07 AM

Good call on stock. I'd venture it is carbon build up, HPFP or fuel related. How many miles on car?

Munchi435i · 08-28-2019, 06:20 AM

Clean your MAF would be my suggestion. How many miles on the car?

JaredG_F30 · 08-28-2019, 07:48 AM

I had a similar issue a while back. I turned cold start back on and changed the cold start RPM to 850, I believe OEM setting is around 1150, to reduce the loud exhaust note upon cold start. This fixed my issue.

Quote:

Originally Posted by HH1815

I have a rough idling at cold start. After a minute is fixes itself however if I slightly feather the gas pedal between roughly 850 -1000 I see my rpm go up a little bit to 1000 then drop down to about 550rpm and the engine starts shaking/idling really rough until I depress the pedal. I initially thought it was the plugs so I changed them to the 97506 .22 gap however its still happening. My next idea is to enable the cold start back to stock setting on the bm3 tune.

I'm n55 ewg w/ do, cp, injen intake, stg1 bm3.

Any ideas on why it might do that? I don't have codes either

HH1815 · 08-31-2019, 03:45 AM

Quote:

Originally Posted by JaredG_F30

I had a similar issue a while back. I turned cold start back on and changed the cold start RPM to 850, I believe OEM setting is around 1150, to reduce the loud exhaust note upon cold start. This fixed my issue.

UPDATE
I changed the cold start to OEM, and it fixed it! like you said Jared, it is loud at 1150ish. I might have to play around with the rpm setting and see if it stays quiet and fixes the idle all together.

Thanks everyone.
Btw I'm at 46xxx miles guys.

08-28-2019, 04:30 AM	#1
HH1815 Enlisted Member 20 Rep 39 Posts Drives: '15 BMW 335i 6mt Join Date: Jun 2019 Location: NY/DE iTrader: (0)	Rough idle during slight pedal press I have a rough idling at cold start. After a minute is fixes itself however if I slightly feather the gas pedal between roughly 850 -1000 I see my rpm go up a little bit to 1000 then drop down to about 550rpm and the engine starts shaking/idling really rough until I depress the pedal. I initially thought it was the plugs so I changed them to the 97506 .22 gap however its still happening. My next idea is to enable the cold start back to stock setting on the bm3 tune. I'm n55 ewg w/ do, cp, injen intake, stg1 bm3. Any ideas on why it might do that? I don't have codes either
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08-28-2019, 05:07 AM	#2
Marlinman First Lieutenant 101 Rep 316 Posts Drives: 2013 335i xDrive Join Date: Jun 2015 Location: MD iTrader: (0)	Good call on stock. I'd venture it is carbon build up, HPFP or fuel related. How many miles on car?
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08-28-2019, 06:20 AM	#3
Munchi435i Major 485 Rep 1,105 Posts Drives: 2014 Alpine White 435i M-sport Join Date: Jun 2017 Location: Orlando FL iTrader: (0)	Clean your MAF would be my suggestion. How many miles on the car?
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