[bato1of3]

Hopefully someone can help. I have a 2008 335xi coupe and it is misfiring badly. The first time this happened, I replaced the spark plugs and it was fine. It started doing it again so I took it to the dealer and they told me I needed fuel injectors. They replaced them and it didnt fix the problem. Took it somewhere else and they found a bad ignition coil, replaced it, and car is still acting up. Has anyone else had this issue and if so, what ended up being the problem? Thanks guys.

[straightcashhomie]

how many miles? carbon buildup?

[g0at23]

My car is in the shop right now with same problem... Eventually it will become undrivable with smoke coming out of exhaust. They said its "probably" a injectors problem.

[bato1of3]

Around 97,000. carbon build up where? the valves?

[jaykayelemenohpee]

Find the cylinder thats misfiring by checking the codes. Swap the coil packs from non-misfiring cylinders to the misfiring ones. If they still misfire its not the packs. Then check the plugs. If theyre fine then injectors and so on and so forth. Knock it out systematically and dont go wasting money.

[e90domz]

Originally Posted by bato1of3

Hopefully someone can help. I have a 2008 335xi coupe and it is misfiring badly. The first time this happened, I replaced the spark plugs and it was fine. It started doing it again so I took it to the dealer and they told me I needed fuel injectors. They replaced them and it didnt fix the problem. Took it somewhere else and they found a bad ignition coil, replaced it, and car is still acting up. Has anyone else had this issue and if so, what ended up being the problem? Thanks guys.

If you replaced the injectors already then try replacing ALL your Coils ($15) Each one) and double check plugs.. if thats not the problem then its prob something to do with your software... if you have any tune try remove it (JB4)(Cobb).

[bato1of3]

The car isnt throwing any codes which is why its makes this so difficult. I guess what makes it worse is that the dealer doesnt have a clue what they are doing either so I had to take it somewhere else. I would replace all the coils but around here they are $75 each, where do you get them for $15?

[DJtoad]

Originally Posted by e90domz

If you replaced the injectors already then try replacing ALL your Coils ($15) Each one) and double check plugs.. if thats not the problem then its prob something to do with your software... if you have any tune try remove it (JB4)(Cobb).

$15 for a coil pack? I don't think so -- more like $45-50. OP, you're way over due for a good walnut blasting of the intake valves. I'm at 60K miles and have had it done twice in my 535 (once under warranty and once out of picket)i. The cost is around $400 at an indy, twice that at a dealer. Check the regional forums for a recommended indy in your area who has a BMW Group carbon blaster. My car runs MUCH better afterwards -- no missing, linear acceleration, and a smooth idle. Unfortunately, it's now widely considered a routine maintenance item for direct injection engines.

[bato1of3]

Thanks a lot! hopefully that fixes it. so annoying.

[critical05]

Originally Posted by straightcashhomie

how many miles? carbon buildup?

+1

[jakobv84]

+1 on trying carbon blasting before spending more time on diagnostics and parts.

[BobbyGuns]

Ignition coil!!!!!!!!!!

[07lilredwagon]

do the ignition coil test by swapping them around...but honestly, it should be throwing a code for that!.....

JP

[Handsomecore]

Originally Posted by bato1of3

Hopefully someone can help. I have a 2008 335xi coupe and it is misfiring badly. The first time this happened, I replaced the spark plugs and it was fine. It started doing it again so I took it to the dealer and they told me I needed fuel injectors. They replaced them and it didnt fix the problem. Took it somewhere else and they found a bad ignition coil, replaced it, and car is still acting up. Has anyone else had this issue and if so, what ended up being the problem? Thanks guys.

I had the same problem . Happened to me about 3 times and it always was the ignition coil they changed which everyone was misfiring and that fixed the problem.