changed plugs, jerky idle (sometimes)
#1
Super Member
Thread Starter
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!
#2
MBWorld Fanatic!
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.
#4
Super Member
Thread Starter
I've taken the maf off twice now to clean it. reset the ecu. doesn't help. I guess I can try different plugs, or a new MAF. or let the dealer calibrate it again. le sigh
#6
Super Member
Thread Starter
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.
#7
MBWorld Fanatic!
I bet they will charge you cost markup and labor on 16 plugs, maf, ecu cal, and a hose change that you forgot to reinstall
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#8
Super Member
Thread Starter
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.
#10
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Join Date: Jun 2008
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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.
![EEK!](https://mbworld.org/forums/images/smilies/eek.gif)
#11
Super Member
Thread Starter
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?
#12
MBWorld Fanatic!
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