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Discussion Starter · #1 ·
My engine makes little shudders and trembles when it idles, no real drop in RPM, runs fine and smooth while driving.
Shudder in P R N and D.

Newish plugs, oem Volvo (2000miles ago)
New WIX airfilter
PCV replaced, did the glove test after and the glove is sucked right in there.
185k miles
No CEL´s

Someone suggested Engine mounts.

Felt to check in here to see if anyone had any suggestion on what to check.

Thanks
 

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Is it a constant shudder or intermittent?
Unplug the MAF, does it run better?

If it's constant then I'd check/inspect/service:
- Injectors
- Fuel filter
- Vacuum leaks
- MAF
- Fuel Trims (via OBDII)
- Compression

I sometimes notice a random and very faint shudder at idlen, durring the shudder my AFR will swing from approx 12.5-16. and I can only relate it to two causes.
1. EVAP purge valve: From my reading (and limited understanding) when the purge valve is opened it will cause a richer AF mixture. The ECU looks for this added fuel to diagnoise if the EVAP system is functioning properly.
2. Catalitic Converter Diagnostics: The ECU will swing the AFR then uses the signals from the front and rear O2 sensors to diagnose the cats efficiency, as well to maintain proper operation and temperature of the catalyst media.

The shudder I feel is very faint, but is there. I normally don't notice it unless I'm paying particular attention to the idle. I've just ruled this out as normal and have not worried about it. If it's excessive shudder then I'd check your spark plugs and spark gap.

PS: This is my 1234th post. :D
 

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I have the same very faint and occasional shudder as Antherzoll on my '04 XC70. It seems totally benign to me, and until I have evidence to the contrary, I have decided not to worry about it.
 

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Discussion Starter · #4 ·
Is it a constant shudder or intermittent?
Unplug the MAF, does it run better?

If it's constant then I'd check/inspect/service:
- Injectors
- Fuel filter
- Vacuum leaks
- MAF
- Fuel Trims (via OBDII)
- Compression

I sometimes notice a random and very faint shudder at idlen, durring the shudder my AFR will swing from approx 12.5-16. and I can only relate it to two causes.
1. EVAP purge valve: From my reading (and limited understanding) when the purge valve is opened it will cause a richer AF mixture. The ECU looks for this added fuel to diagnoise if the EVAP system is functioning properly.
2. Catalitic Converter Diagnostics: The ECU will swing AFRs and use the signals from the front and rear O2 sensors to diagnose the cats efficiency, as well to maintain proper operation and temperature of the catalyst media.

The shudder I feel is very faint, but is there. I normally don't notice it unless I'm paying particular attention to the idle. I've just ruled this out as normal and have not worried about it. If it's excessive shudder then I'd check your spark plugs and spark gap.

PS: This is my 1234th post. :D
It is intermittent, every now and then, but every day, every drive as far as i can tell, seems like it does it more when the engine is hot and has been running for a long day, noticed it the most after about 150miles of driving in +85 degree weather.

Ill try unhooking the MAF, if it runs better would it indicate cleaning it ?

So how about the engine mounts?
My top mount was worn and caused hard garage shifts when going from P to R or D, so it would make sense to me if the engine mounts are worn it could cause shudders and worsen with heat?

Yay 1234, it was 1235 when i read it though :) such fleeting moments of joy.
 

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Discussion Starter · #5 ·
I have the same very faint and occasional shudder as Antherzoll on my '04 XC70. It seems totally benign to me, and until I have evidence to the contrary, I have decided not to worry about it.
Hmm, yea, somehow i keep looking for problems :)
 

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Discussion Starter · #6 ·
So today i got an engine code, p0302, cylinder 2 misfire.

185k miles on the car, changed air filter yesterday to see if that would help with the shudder, no change, plugs where changed 2k miles ago, they are volvo R6 with 1 prong on them.
Fully synth oil, recently changed PCV system.

Grateful for any pointers and direction.

Thanks
 

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Swap the ignition coil on cylinder 2 with another cylinder and see if the misfire follows it. If so, then the ignition coil is faulty.

An engine mount wouldn't cause an intermittent shudder
 

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Discussion Starter · #8 ·
Swap the ignition coil on cylinder 2 with another cylinder and see if the misfire follows it. If so, then the ignition coil is faulty.

An engine mount wouldn't cause an intermittent shudder
will try this, thanks
as for the plugs , should there be 3 prongs on the plug?
 

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will try this, thanks
as for the plugs , should there be 3 prongs on the plug?
Only for NA cars. Turbo plugs only have one electrode.
 

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Discussion Starter · #10 ·
Ok cool. Thanks. Changed the coil from 2 to 1. Hope this is it. Are the bosh ones on ipd ok to get? Or should i get genuine volvo coils if that is whats wrong?
 

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Discussion Starter · #13 ·
Bosch = OEM
Great, thanks!

i have never before hoped a check engine light would come on. But this time imá praying for that light to come on and read P0301
 

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These 5 bangers like to destroy the passenger side lower motor mount, both of the Volvos I have came into my possession with them trashed anyways. I think with the passenger side front wheel off, I could get a pry bar on the head of one of the mount bolts and lift the engine up. The rest of the mounts seemed alright. Really made a difference on the smooth riding XC90 I can't trust to restart if I take it anywhere now, new one made the S70 felt more like a heap than it already is, but hey at least it's a heap I can rely on to get me to work everyday. Sometimes if the stars align, I can put a perfect condition cd into the s70 radio, and it won't even skip!
 

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I have the same very faint and occasional shudder as Antherzoll on my '04 XC70. It seems totally benign to me, and until I have evidence to the contrary, I have decided not to worry about it.
Yep, I do as well. Have never really worried about it.


2002 V70XC, 2003 V40, 2004 S60, 2010 V70
 
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