Loss of power, rough idle with 94k miles

CameroN7887 · 07-10-2018, 02:06 AM

So lately I've been experiencing a big loss in power but it's been intermittent up until about a week or two ago. Some days I'd touch the pedal barely and it would get up and go easily, and other days it took a lot more gas to get the car to accelerate how it did before. Now recently it has been idling rough, giving me more vibrations in the cabin than I'm used to. The acceleration feels sluggish and like it doesn't pull as hard as it used to high up in the rpms past about 4K. Looking at the repair history the camshaft position sensor got replaced around 25k miles ago, and as far as I know spark plugs and coils haven't been done yet, and I'm bouncing back and forth between spark plugs/coil packs and maybe a problem with the VANOS somewhere? Any help would be greatly appreciated guys!

sorin1987 · 07-10-2018, 03:14 AM

I had similar symptoms. Sometimes the car just worked fine, sometimes shaked like an earthquake. For me it was a cracked valve cover...too much air was getting into the engine for the amount of petrol the injectors were spitting into the cylinders. The crack was barely visible with the naked eye but it was there.
The result on the OBD2 reader were misfires on all 6 cylinders and oxygen sensors were throwing an error "the mix of air and petrol too rich".
It can also be spark plugs and vanos as you said. For me it was quite hard to diagnose. I cleaned and swapped around the vanos solenoids myself and a garage changed the NOx sensor and all spark plugs and coils without fixing the issue.
BMW wanted to replace all O2 sensors for a ton of money but didn't let them. An indy discovered the crack in the valve cover and replaced it for just a little more money BMW wanted for their "diagnose" which was wrong anyway.

Bimmer_Engineer · 07-10-2018, 06:57 AM

Have you scanned for codes?

Spark plugs, coils, and vanos are really easy things to do just to eliminate them as a possibility. I personally would do the vanos first followed by the plugs...that will set you back a total of about $75 including the thin wall spark plug socket if you don’t have it.

If that doesn’t work then you could consider the coils next although they will run about $180-$200...

CameroN7887 · 07-10-2018, 07:28 PM

I did run the codes using ISTA and nothing came up which was the annoying part, would you recommend cleaning the VANOS or replacing? It's funny you say a cracked valve cover as I do hear like a slight whistling sound somedays, but no where near as bad as the blown PCV whistle, almost like a quieter lower tone sound. Figured I'd try coils and spark plugs to get them out of the way first, but if I can clean the VANOS solenoids somehow I would, and I might as well try doing the plugs as well, where would I be able to get the thin wall spark plug socket?

Bimmer_Engineer · 07-10-2018, 08:09 PM

The coils and the vanos both there codes for me so that might not solve the issue for you but they’re cheap and worth a shot. The spark plugs just helped the idle for me. I bought this socket from amamzon.

https://www.amazon.com/dp/B01MXJ3X7P..._mHUNsiTMNw3cM

CameroN7887 · 07-11-2018, 02:09 AM

Was reading into some of the symptoms of a failing CCV and heard about suction on the oil filler cap being a symptom of a bad CCV but wasn't sure as I don't have the horrible whistling sound, but I lifted my oil filler cap with the car idling and it took some force to lift off and sounded like air brakes relieving themselves, I left the cap off for a sec to check the idle rpms and it was fine, but as I was walking back to the engine bay the car seemed to hiccup badly, (sounded like it was about to stall) then caught itself so I put the cap back on and turned the car off. Is it safe to say that the loss of power and rough idle could be my CCV going bad?

07-10-2018, 02:06 AM	#1
CameroN7887 Private 28 Rep 88 Posts Drives: 2008 BMW 328i Join Date: Apr 2018 Location: Arizona, USA iTrader: (0)	Loss of power, rough idle with 94k miles So lately I've been experiencing a big loss in power but it's been intermittent up until about a week or two ago. Some days I'd touch the pedal barely and it would get up and go easily, and other days it took a lot more gas to get the car to accelerate how it did before. Now recently it has been idling rough, giving me more vibrations in the cabin than I'm used to. The acceleration feels sluggish and like it doesn't pull as hard as it used to high up in the rpms past about 4K. Looking at the repair history the camshaft position sensor got replaced around 25k miles ago, and as far as I know spark plugs and coils haven't been done yet, and I'm bouncing back and forth between spark plugs/coil packs and maybe a problem with the VANOS somewhere? Any help would be greatly appreciated guys!
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07-10-2018, 03:14 AM	#2
sorin1987 Private First Class 38 Rep 112 Posts Drives: BMW 520i G31 MSport Join Date: Sep 2016 Location: London iTrader: (0)	I had similar symptoms. Sometimes the car just worked fine, sometimes shaked like an earthquake. For me it was a cracked valve cover...too much air was getting into the engine for the amount of petrol the injectors were spitting into the cylinders. The crack was barely visible with the naked eye but it was there. The result on the OBD2 reader were misfires on all 6 cylinders and oxygen sensors were throwing an error "the mix of air and petrol too rich". It can also be spark plugs and vanos as you said. For me it was quite hard to diagnose. I cleaned and swapped around the vanos solenoids myself and a garage changed the NOx sensor and all spark plugs and coils without fixing the issue. BMW wanted to replace all O2 sensors for a ton of money but didn't let them. An indy discovered the crack in the valve cover and replaced it for just a little more money BMW wanted for their "diagnose" which was wrong anyway.
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07-10-2018, 06:57 AM	#3
Bimmer_Engineer Lieutenant Colonel 1044 Rep 1,667 Posts Drives: 2007 335i Join Date: May 2018 Location: Louisiana iTrader: (0) Garage List 2008 Porsche Boxster [0.00] 2016 Mercedes Benz ... [0.00] 2007 BMW 335i [9.50]	Have you scanned for codes? Spark plugs, coils, and vanos are really easy things to do just to eliminate them as a possibility. I personally would do the vanos first followed by the plugs...that will set you back a total of about $75 including the thin wall spark plug socket if you don’t have it. If that doesn’t work then you could consider the coils next although they will run about $180-$200...
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07-10-2018, 07:28 PM	#4
CameroN7887 Private 28 Rep 88 Posts Drives: 2008 BMW 328i Join Date: Apr 2018 Location: Arizona, USA iTrader: (0)	I did run the codes using ISTA and nothing came up which was the annoying part, would you recommend cleaning the VANOS or replacing? It's funny you say a cracked valve cover as I do hear like a slight whistling sound somedays, but no where near as bad as the blown PCV whistle, almost like a quieter lower tone sound. Figured I'd try coils and spark plugs to get them out of the way first, but if I can clean the VANOS solenoids somehow I would, and I might as well try doing the plugs as well, where would I be able to get the thin wall spark plug socket?
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07-10-2018, 08:09 PM	#5
Bimmer_Engineer Lieutenant Colonel 1044 Rep 1,667 Posts Drives: 2007 335i Join Date: May 2018 Location: Louisiana iTrader: (0) Garage List 2008 Porsche Boxster [0.00] 2016 Mercedes Benz ... [0.00] 2007 BMW 335i [9.50]	The coils and the vanos both there codes for me so that might not solve the issue for you but they’re cheap and worth a shot. The spark plugs just helped the idle for me. I bought this socket from amamzon. https://www.amazon.com/dp/B01MXJ3X7P..._mHUNsiTMNw3cM
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07-11-2018, 02:09 AM	#6
CameroN7887 Private 28 Rep 88 Posts Drives: 2008 BMW 328i Join Date: Apr 2018 Location: Arizona, USA iTrader: (0)	Was reading into some of the symptoms of a failing CCV and heard about suction on the oil filler cap being a symptom of a bad CCV but wasn't sure as I don't have the horrible whistling sound, but I lifted my oil filler cap with the car idling and it took some force to lift off and sounded like air brakes relieving themselves, I left the cap off for a sec to check the idle rpms and it was fine, but as I was walking back to the engine bay the car seemed to hiccup badly, (sounded like it was about to stall) then caught itself so I put the cap back on and turned the car off. Is it safe to say that the loss of power and rough idle could be my CCV going bad?
	Appreciate 0 Quote