changed plugs, jerky idle (sometimes)
Thread Starter
Super Member
Joined: Jun 2008
Posts: 855
Likes: 1
2010 C63
changed plugs, jerky idle (sometimes)
Good morning everyone and happy 4th of July!
So here is my problem. Last weekend I decided to change my spark plugs. I picked up 16 Bosch 9652 - Iridium OE Finewire plugs from AutoZone as was recommended by their computer as a factory replacement. My previous set was NGK (one step colder) however I don't recall the part number. At any rate, I performed the following:
-replaced all 16 plugs
-cleaned my MAF
-cleaned my air filters with MAF cleaner spray
-cleaned the throttle body with throttle body spray
I also reset the ECU as I usually do after cleaning my air filters and MAF. When I started the car, everything seemed ok. However, when I put the car into reverse or drive the engine starts to stumble. It's like the idle is too low and the motor shakes. Sometimes it will stall. When I'm driving though, everything is fine. Car pulls strong.
I don't know if I need to take it in to the dealer and have the MAF re-calibrated, or maybe the spark plugs are causing the issue. I get a PO101 and a PO400 after driving a while. I'm not sure how it would have gone out of calibration by changing plugs but you never know. I also don't know how I could have messed with the EGR circuit but again, I'm no expert here.
Did I put the wrong plugs in? What is the best thing to do now?
thanks for any help!
So here is my problem. Last weekend I decided to change my spark plugs. I picked up 16 Bosch 9652 - Iridium OE Finewire plugs from AutoZone as was recommended by their computer as a factory replacement. My previous set was NGK (one step colder) however I don't recall the part number. At any rate, I performed the following:
-replaced all 16 plugs
-cleaned my MAF
-cleaned my air filters with MAF cleaner spray
-cleaned the throttle body with throttle body spray
I also reset the ECU as I usually do after cleaning my air filters and MAF. When I started the car, everything seemed ok. However, when I put the car into reverse or drive the engine starts to stumble. It's like the idle is too low and the motor shakes. Sometimes it will stall. When I'm driving though, everything is fine. Car pulls strong.
I don't know if I need to take it in to the dealer and have the MAF re-calibrated, or maybe the spark plugs are causing the issue. I get a PO101 and a PO400 after driving a while. I'm not sure how it would have gone out of calibration by changing plugs but you never know. I also don't know how I could have messed with the EGR circuit but again, I'm no expert here.
Did I put the wrong plugs in? What is the best thing to do now?
thanks for any help!
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Joined: Nov 2001
Posts: 1,289
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From: OC
C32
Sounds like the cleaning of the MAF may have done something to it. Could be the plugs but doubt it. You can always re-install the old plugs to see but that is a lot of work.
I would drive it for a while to see if it cures itself. If there is contaminants on the MAF they may burn off with time.
This is why I try not to do more than one thing at a time (changing plugs&cleaning MAF) as if there is a problem you never know which step caused it.
I would drive it for a while to see if it cures itself. If there is contaminants on the MAF they may burn off with time.
This is why I try not to do more than one thing at a time (changing plugs&cleaning MAF) as if there is a problem you never know which step caused it.
Thread Starter
Super Member
Joined: Jun 2008
Posts: 855
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2010 C63
I reluctantly dropped my C55 off at the stealership this morning to have the diagnostics done. I'll report back once the culprit is found. I'm guessing they will replace the MAF and recalibrate the ecu.
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Thread Starter
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Joined: Jun 2008
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2010 C63
Well, hmm. They replaced my EGR valve, said it was sticking open causing the idle issues. The transducer was probably damaged while I was cleaning the throttle body with TB cleaner. Be careful not to get that TB cleaner on any electrical stuff!
They also replaced my MAF. When I got the car back, it was leaking radiator fluid.
SOOOO, I went back in and asked them to fix that issue. they said it was a leaky radiator tank and it will be 41000 to replace the radiator.
I don't know if I handled that news properly, since I threw a little bit of a fit. The manager decided they would pay 50% since the leak began while it was in their service, even though there is no evidence to say that the leak was caused by them.
I guess it was just my good fortune that this happened while it was with them so they would pay 50%?
I'm still not happy. Never had any sort of issue like that and the service manager said since my car has so many miles that things like this will happen. I guess he's right.
They also replaced my MAF. When I got the car back, it was leaking radiator fluid.
SOOOO, I went back in and asked them to fix that issue. they said it was a leaky radiator tank and it will be 41000 to replace the radiator.
I don't know if I handled that news properly, since I threw a little bit of a fit. The manager decided they would pay 50% since the leak began while it was in their service, even though there is no evidence to say that the leak was caused by them.
I guess it was just my good fortune that this happened while it was with them so they would pay 50%?
I'm still not happy. Never had any sort of issue like that and the service manager said since my car has so many miles that things like this will happen. I guess he's right.
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Senior Member
Joined: Jun 2008
Posts: 300
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From: ATL
05 C55 AMG
Well, hmm. They replaced my EGR valve, said it was sticking open causing the idle issues. The transducer was probably damaged while I was cleaning the throttle body with TB cleaner. Be careful not to get that TB cleaner on any electrical stuff!
They also replaced my MAF. When I got the car back, it was leaking radiator fluid.
SOOOO, I went back in and asked them to fix that issue. they said it was a leaky radiator tank and it will be 41000 to replace the radiator.
I don't know if I handled that news properly, since I threw a little bit of a fit. The manager decided they would pay 50% since the leak began while it was in their service, even though there is no evidence to say that the leak was caused by them.
I guess it was just my good fortune that this happened while it was with them so they would pay 50%?
I'm still not happy. Never had any sort of issue like that and the service manager said since my car has so many miles that things like this will happen. I guess he's right.
They also replaced my MAF. When I got the car back, it was leaking radiator fluid.
SOOOO, I went back in and asked them to fix that issue. they said it was a leaky radiator tank and it will be 41000 to replace the radiator.
I don't know if I handled that news properly, since I threw a little bit of a fit. The manager decided they would pay 50% since the leak began while it was in their service, even though there is no evidence to say that the leak was caused by them.
I guess it was just my good fortune that this happened while it was with them so they would pay 50%?
I'm still not happy. Never had any sort of issue like that and the service manager said since my car has so many miles that things like this will happen. I guess he's right.
WTF 41000 to replace the radiator??? Mine was leaking from the driverside of the radiator last week and had it replaced at my indy shop for under $700 w/labor.
Thread Starter
Super Member
Joined: Jun 2008
Posts: 855
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2010 C63
haha oops, yea they wanted $1000. I got it for half price, radiator, coolant, and thermostat replacement.
Strangely, now, all of a sudden, my transmission NO LONGER SLIPS.... WTF?
Strangely, now, all of a sudden, my transmission NO LONGER SLIPS.... WTF?
MBWorld Fanatic!
Joined: Jun 2006
Posts: 2,359
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From: California
06 C55, 09 E350
Good thing you took it in instead of tinkering with it anymore. Probably would have ended up spending even more money in the long run. Things like that will happen, my water pump just started going out on my so I will need to change that soon. I just touched 130k miles
