06 X3 misfires

When I accellerate to merge etc.the engine sounds good till just before it shifts from 3rd to 4th gear (auto trans.).Then it seems to mis fire a bit until it shifts.I put in a bottle of seafoam,and have just replaced the plugs .Plug #2 had oil all over it ,even up the sides of it.
Cleaned up the oil & installed new plug ,but car still misfires with hard accelleration at about 4000 rpm.in 3rd gear.With reving in park or regular accell.it runs good.What could it be???
Car is an 06 3.0 with 86k.miles (car orig.from USA)

Originally Posted by ncord

When I accellerate to merge etc.the engine sounds good till just before it shifts from 3rd to 4th gear (auto trans.).Then it seems to mis fire a bit until it shifts.I put in a bottle of seafoam,and have just replaced the plugs .Plug #2 had oil all over it ,even up the sides of it.
Cleaned up the oil & installed new plug ,but car still misfires with hard accelleration at about 4000 rpm.in 3rd gear.With reving in park or regular accell.it runs good.What could it be???
Car is an 06 3.0 with 86k.miles (car orig.from USA)

That sounds like you need to replace the valve gasket cover if your getting oil up in the plugs.

Throwing any codes? If so, list them

No codes,and oil is only on one plug.I was wondering if it was a bad plug coil

Replaced VCG and spark plug seals .Cleaned plug that had oil in tube ,and cleaned MAF sensor with spray.Car runs great until I accelerate up hills between 3 & 4000 rpm
and then it misfires.Idles smooth and is good on acceleration below that.What could it be???

since it is just one cylinder that you are having the issue with, there is only a few things it could be...I would put money on a bad coil pack, possibly the coil connector?

Originally Posted by ncord

When I accellerate to merge etc.the engine sounds good till just before it shifts from 3rd to 4th gear (auto trans.).Then it seems to mis fire a bit until it shifts.I put in a bottle of seafoam,and have just replaced the plugs .Plug #2 had oil all over it ,even up the sides of it.
Cleaned up the oil & installed new plug ,but car still misfires with hard accelleration at about 4000 rpm.in 3rd gear.With reving in park or regular accell.it runs good.What could it be???
Car is an 06 3.0 with 86k.miles (car orig.from USA)

My '08 does something similar... It sometimes feels like it "hesitates" but only under heavy acceleration. I'm due for new plugs in roughly 25k miles, but may replace them and the ignition coils much sooner.. Someone also has suggested replacing the O2 sensors, but those are expensive and should last way past 100k miles..

My plan is to keep running Techron through the system every could thousand miles (no seafoam), then replace the plugs..then the coils.

Originally Posted by brewder

My '08 does something similar... It sometimes feels like it "hesitates" but only under heavy acceleration. I'm due for new plugs in roughly 25k miles, but may replace them and the ignition coils much sooner.. Someone also has suggested replacing the O2 sensors, but those are expensive and should last way past 100k miles..

My plan is to keep running Techron through the system every could thousand miles (no seafoam), then replace the plugs..then the coils.

Why not seafoam?

Originally Posted by mrsanchez3

Why not seafoam?

Because I haven't found a single person on Bimmerfest that speaks highly of it for our cars... Not to mention that BMW recommends Techron as the fuel system cleaner of choice. So i'm sticking with that.

Originally Posted by brewder

Because I haven't found a single person on Bimmerfest that speaks highly of it for our cars... Not to mention that BMW recommends Techron as the fuel system cleaner of choice. So i'm sticking with that.

Gotcha... Thank you... I haven't used any of this stuff... I've actually never used fuel cleaner on any car I've ever had... So, I was wondering if you'd used both... Thanks!

Originally Posted by brewder

My '08 does something similar... It sometimes feels like it "hesitates" but only under heavy acceleration. I'm due for new plugs in roughly 25k miles, but may replace them and the ignition coils much sooner.. Someone also has suggested replacing the O2 sensors, but those are expensive and should last way past 100k miles..

My plan is to keep running Techron through the system every could thousand miles (no seafoam), then replace the plugs..then the coils.

It doesn't make sense to replace the coils. They're like light bulbs, either they're on or off. There is no in between.

I am going to butcher the explanation but one of the users on here recently gave a through reason why seafoam doesn't work with our engine. I will have to find the thread when I have a moment but it had something to do with our engine design is not compatible with what seafoam is designed to do. It won't harm anything but it won't help either.

It was one cylinder that had oil in it but I changed the VCG & plug seals,so that should be good now.But it is still missing when under load around 4000rpm.

Hesitation under load and no CEL, could be a sign of gas starvation. It could be just a clogged fuel filter or a fuel pump going bad. But in order to diagnose a fuel pump, you need special equipment to measure fuel pressures.
Also O2 sensors have been known to produce hesitation under acceleration when they start to fail, although not triggering a CEL.

Found this article:
http://www.aa1car.com/library/fuel_pump_diagnose.htm

Do you think it could be Transmission problems???