mmike

Hey guys-

i've got a '08 GL450 and it seems that during idle rpm's the car is jerky and stutters. anyone experiencing similar problems?

alfordvette

I had a problem that may be similar to your issue. At a stop light or sign, the engine seemed to have a slight miss. I took it to dealer and it replaced the head on the passenger side of engine under warranty (approx. 49,000 miles on vehicle at the time). Service director said several of the exhaust valves were not properly aligned and wore the area where they seat unevenly and the seal was not correct. (Please forgive my use of terminology-I am not a mechanic and the vehicle is in my lower garage, which is too far away for me to go get the work order at this time.) He also said this was a problem they had seen before. Further, he said MB was aware of this problem and authorized the repair without hesitation.

Regards

MercedesGL_ftw

Do you have CEL on? What's mileage? On freeway,do you feel less power?

mmike

CEL is not on. Mileage is around 32k. Can't really tell if there's power loss on fwy. Essentially when I put the gear into drive and let it go without any acceleration it seems to stutter and "vibrate" alot. doesn't seem like engine misfired or something

MercedesGL_ftw

I would suggest you check the big vacuum line on top of engine under the plastic cover. Sometimes after service, it is not put back on all the way. Also, make sure to always use premium gas. Lower octane gas can make jerky/vibration when stopping. It's hard to say, since CEL is not on and diagnostics can't be run for codes. May be camshaft/crankshaft sensor replacement is due?

mmike

Hmm.. ill bring it by the dealer and make them check these things out! thanks for the advice guys

bmiller264

I have a 2008 GL450 with the same symptoms you are describing here. It started about a month ago. And it is really noticable when in traffic - like in a construction zone where you want to move ahead slowly as the traffic inches forward. Letting my foot off the brake and not touching the accellerator it will stutter forward - sometimes throwing my and the passengers head back into the headrest.

I brought it in for service yesterday. They looked at it almost all day - did a "software upgrade" - but weren't able to solve the issue. The service rep took it for a drive today and noticed it doing the same thing that I described when I brought it in. He then talked with his head mechanic and they decided this was normal operation for this model of Mercedes. Really?!?!?? It never did it before -and started a month ago.

Actually, it started the day that I got it back from service a month ago. They replaced the front right shock/strut (whatever it's called). It was leaking air and the front right (and eventually the left right as well) of the GL450 was totally down. That repair took almost a week as they didn't have the parts in stock.

I can't imagine replacing a shock absorber could have any affect on the transmission/engine at idle speed.

Other notes: The tach does not move when this happens - it stays steady at around 500. It almost seems like a transmission problem.

Applying a little gas takes care of the problem - but who in the h*ll wants to do that - especially when you're driving in traffice and only moving slowly forward.

I'm leaving now to go pick it up from service - printed out this thread to bring it along with me.

I was thinking of asking the sales rep if I could test drive another of their CPO GL450's ... and then have them drive mine. There's no way this is normal operation. If it was on their lot - they couldn't sell it.

bmiller264

mmike - did they ever find out what the problem was with your GL450?

Mr.OgPepper

Any updates?

mmike

Late response, but never too late i guess! Brought it to the dealer and they couldn't find anything. i just left it alone, and try to ignore it. anyone else here experiencing similar issues?

BlownV8

I've also noticed a rough idle at times.

cougar69

Hi bmiller264,

How did it go eventually?

cougar69

I think my 2010 gl450 is experiencing the smiliar issue...

mmike

still having the same issue- dealer couldn't do anything about it..

alx

off the top of my head... this is what i have seen documented about this problem

unplugged vacuum hose - inspect all vacuum hoses

tps lost calibration- perform tps initialization/ learning via das

dirty throttle body - clean tb

bad gas / dirty injectors - run a bottle or two of techron

dirty fuel filter - replace

dirty air filters - replace

bad engine/ trannny mounts - replace

but most likely- bad driveshaft rubber "cake" (damper) - replace

also jerky low-speed shifting of the 7g tranny might be indicative of in-tranny conduit plate going bad

crniamg

any one got this problem fix drive me

nick 55

Guys, I am a former MB tech(moved on to engineering now at a different company) and this issue is in fact worn valve guides in the head. I have never seen it anywhere but the passenger side head and you may not get codes for it. What the dealer needs to do is run a compression test with their laptop. I have started suffering this same symptom in my GL550 in the last month.

Nick

crniamg

just touch on gas pedal and stop that jerking i need to do that test and c that thanks man

crniamg

i don't have rough idle runs good i replace the spark plugs and variable intake manifold switchover valve i got aluminum one reset all the adaptation just that jerking and its not all the time sometime trany shift nice going

alx

you wear the valve guides a little stutter at idle is going to be the least of your problems. oil consumption for one will go through the roof among other ugly and very visible symptoms.

and i am not aware of any way to run compression test via das. how is it done?

the idle problem on most cars is traced back to dirty injectors or carbon deposits in head(s). run a bottle or two of chevron techron and if problem not gone- look elsewhere.

crniamg

i just did not have much time to play i got busy at shop i need to look my air mass bc this morning was cold and any time its cold wont do that just when its hot outside maybe one day i get this fix i have no loss of power no oil problem just that jerking on low rpm when you stop completely and you just let go of brake if you just tuch the gas pedal no more jerking

o btw sorry for my spieling that is my bad side

nick 55

You won't see much of an oil consumption issue. You can doubt me all you want, but since the valve guides wear at the base of the stems, the seals maintain decent sealing. But what do I know, I have zero experience with these.

Nick

tahir

i am having the same problem with my 07 GL450 . the jerks are not too voilent but i would like to rectify it. i would try to check vacuum hose and check but i have a slight problem. with the show of a picture or a description, could anyone confirm the location of vacuum hose and head? just want to be dead sure before i do something myself. thanks

alx

Remove the filter boxes/ intake tubes. You will see it.

crniamg

do you have check engine light