Idle problem - Plugs vs mounts
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Joined: Feb 2008
Posts: 13
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From: Dallas, TX
2000 S430
Idle problem - Plugs vs mounts
I have a 2000 S430 that has always idled very smoothly. Recently I began to have random misfire codes. I replaced all 16 plugs with NGK platinum. The old plugs' electrodes were definitely worn away. Good news is that the misfire codes are completely gone even after 2000 miles. Problem is that I am now experiencing a very rough idle. RPMs are steady and power is good. My question is ... could a bad plug cause a rough idle yet NOT set a misfire code? I have replaced the plug wires since with no effect on the rough idle. I am leaning towards engine mounts at this point, but still a funny coincidence that they went bad right after a spark plug change.
Any thoughts?
Jeff
Any thoughts?
Jeff
MBWorld Fanatic!
Joined: Jul 2006
Posts: 1,578
Likes: 7
04 S430 (sold),05 X5 4.4i, 02 325i, 87 560SL, 85 Alfa Romeo
I have a 2000 S430 that has always idled very smoothly. Recently I began to have random misfire codes. I replaced all 16 plugs with NGK platinum. The old plugs' electrodes were definitely worn away. Good news is that the misfire codes are completely gone even after 2000 miles. Problem is that I am now experiencing a very rough idle. RPMs are steady and power is good. My question is ... could a bad plug cause a rough idle yet NOT set a misfire code? I have replaced the plug wires since with no effect on the rough idle. I am leaning towards engine mounts at this point, but still a funny coincidence that they went bad right after a spark plug change.
Any thoughts?
Jeff
Any thoughts?
Jeff
MBWorld Fanatic!
Joined: Jul 2006
Posts: 1,578
Likes: 7
04 S430 (sold),05 X5 4.4i, 02 325i, 87 560SL, 85 Alfa Romeo
When these mounts collapse, the olnly this you will get is the vibrations at fist. If you et then go, the rubber will break and you will have nothing supporting your engine to the frame so it will start moving when you accelerate causing loss of torque and possible damaging the tranmission mount if it isn't already..
This is not something you want to let go forever...I will do mine in a few weeks and post pics of the process so you will be able to see if this is something you want to do yourself.
MBWorld Fanatic!
Joined: Jan 2007
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From: Toronto
V12TT
The mounts are $118.00 dollars for the set. and are a simple but time consuming DIY. Dealers will charge at least 7 hrs labor so do the math.
When these mounts collapse, the olnly this you will get is the vibrations at fist. If you et then go, the rubber will break and you will have nothing supporting your engine to the frame so it will start moving when you accelerate causing loss of torque and possible damaging the tranmission mount if it isn't already..
This is not something you want to let go forever...I will do mine in a few weeks and post pics of the process so you will be able to see if this is something you want to do yourself.
When these mounts collapse, the olnly this you will get is the vibrations at fist. If you et then go, the rubber will break and you will have nothing supporting your engine to the frame so it will start moving when you accelerate causing loss of torque and possible damaging the tranmission mount if it isn't already..
This is not something you want to let go forever...I will do mine in a few weeks and post pics of the process so you will be able to see if this is something you want to do yourself.
MBWorld Fanatic!
Joined: Jul 2006
Posts: 1,578
Likes: 7
04 S430 (sold),05 X5 4.4i, 02 325i, 87 560SL, 85 Alfa Romeo
MBWorld Fanatic!
Joined: Jan 2007
Posts: 1,986
Likes: 9
From: Toronto
V12TT
do you think only the tranny mounts need replacing or all of them? My car vibrates badly from 100-130km/h you think this is related with the mounts? Does this with my stock wheels and the 19s
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MBWorld Fanatic!
Joined: Jul 2006
Posts: 1,578
Likes: 7
04 S430 (sold),05 X5 4.4i, 02 325i, 87 560SL, 85 Alfa Romeo
As far as the vibration question,
NOPE. No at all..
THat is another problem..YOU need to re-evaluate your wheel situation.. Just because it does it on both sets does not means hat there isn't issue with both sets..
Speed dependent vibration 99% of the time is wheel/Tire related.
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