[Shearer]

Hey everyone,

I have a 2008 335i that's under certified preowned warranty and had some misfiring issues in January this year. With my car around 105k kms, decarbonization was recommended and I have that done at BMW Bellevue.

Misfiring was gone so I was happy. However, the misfiring issues came back 2 weeks ago and I brought it into the dealer again (different one this time, as I live in Canada, but the decarb in Bellevue was $400 instead of the local dealers' $1200 quote). First time I brought it in they replaced ignition coil #5 and gave it back to me. Problem was still there so I brought it in again. This time, they replaced all the injectors and ignition coil #3 and #5. Gave it back to me and there was improvement, but there's still a bit of misfiring at low speed and around 2-2.5k rpm. So I had to go back a third time and now they claim that their diagnostic computer is saying my car requires a decarb. I said I just had it done less than 5k kms ago and showed them proof it was done at a BMW dealership. They said they can't speak for the quality of work at another BMW dealership and that they can't be sure until they take out the intake manifold to check. If it's clean, then they will look elsewhere for issues and cover the bill. But if it's not, then they will charge me $380 to take out the manifold and put it back it.

My question is whether their diagnostic computer can even show them the fault is with carbon buildup? Are they just BSing? I thought that wasn't an official fault code?

Thanks in advance for your advise!

[nick380]

hmmm make sure they insert the decoupling element for the injectors, I have read other people's solution to this and have found out the decoupling element was never properly put back or installed at all. looks like this: http://www.amazon.com/BMW-Genuine-In.../dp/B00G090YX8.

Hope that helps