[Ricapar]

I have an 2009 e93 328i with about 88k miles.

About two weeks ago, I gave it a good go from a stop. Halfway through the check engine light came on, and the car started shaking. Pulled over. The car felt like it was struggling to not stall, but it kept going. I pulled the codes and turned off the car. The code I got was P0303 - Cylinder 3 Misfire.

I turned the car back on, and the check engine light turned off, and things were back to normal. I cleared the codes, and continued on. I later re-scanned, and saw that the Cylinder 3 Misfire was still there as a pending code.

The other day while passing another vehicle the light came on again. Same process - pulled over, shut off, turned back on, and all was well. Check Engine light went off, but the P0303 was still pending.


What I've done so far:

• Swapped ignition coils - No luck.
• Installed a new ignition coil - no luck.
• Swapped spark plugs - no luck.

After all those, cylinder 3 still generates a pending P0303 misfire code.

I looked around as best I could for any frayed wires or something of the sort, but I couldn't see anything out of the ordinary.

The car is not under BMW's warranty, but I do have one of those 3rd party Powertrain warranties from Zurich. I'm debating taking it into the indie shop I trust, but I'd like to tackle this (or at least figure out what is causing the issue) on my own. There's always the risk that the work won't be covered by them.

Any ideas?

[NormE91]

Ugh. Sorry to hear that.

I just got a misfire tonight when I left work. Hoping it's just a coil pack, need to check codes in the morning.

I'll be watching your thread, hopefully someone will have some ideas for you. My only thought after changing all that would be the ecu.

[Blackhawk36]

Next step is the injector. Did you switch them yet?

[Ricapar]

Originally Posted by Blackhawk36

Next step is the injector. Did you switch them yet?

I have not, yet, nope.

I just looked through some guides, and it looks easy enough to do in one day in the driveway. That'll probably be what I spend monday doing.

One thing I did do today was an oil change, put Seafoam in the oil, and some injector cleaning fluid stuff in the gas.

I'll keep the thread updated with whatever I find.

[Titanium3Series]

yea next step in my opinion would be to check the injector out, or make sure with noid light or other means that it is firing in the correct pattern. Also try swapping the injector with a different cylinder of course to see if the code follows to that cylinder.

[MrQuickR1]

The month of misfires?
I too was coming home from work last week when all of the sudden the car would shake bad when accelerating. The light was on and I was 25 minutes away from home at this point on the highway. So I kept my speed and feathered the gas to maintain it. As I got off the highway I hit a small hump in the road and the light went out and stopped shaking.
So after the exit ramp I hit the gas and the light comes back and the shakes are back bad. Now I'm at red lights and feeling like it will stall.
Same symptoms you have. I got home and after a day (snow day) I started the car to move it up to remove snow where it was parked. No light, no shake.
I scan it the next day and shows misfire cyl 2 code 29CE
So for now I figured it is coils and one is loose. But I am not taking the chance so I ordreed 6 coils and plugs, although it's cpo, I don't want 1 new coil or plug, I want it all changed at the same time. I have 2 new coils here but want all 6 new. Anyway we'll see what happens after the change out.

[NormE91]

Mine ended up being cylinder 6 coil. Replaced yesterday and all is well now.

Good luck OP, let us know how you make out.

[Ricapar]

Originally Posted by NormE91

Mine ended up being cylinder 6 coil. Replaced yesterday and all is well now.

Good luck OP, let us know how you make out.

Probably a dumb question, but just to make sure on this: Your misfire was originally on cylinder 6, yes?

[NormE91]

Originally Posted by Ricapar

Probably a dumb question, but just to make sure on this: Your misfire was originally on cylinder 6, yes?

Yes. I moved the coil from 6 to 5 and the misfire followed the coil. Oh, one thing I found out was that you really need to make sure the electrical connection is well seated. Just because the clip snaps closed doesn't mean the connector is fully seated! I ended up with two misfires momentarily because of this

Have you made any progress on yours?