[YungLawn]

I recently bought a 2008 335xi sedan A/T. The car runs fine most of the time, but always shudders hard on a warm start. The rpms also fluctuate around 600 on warm start. I've also noticed the car feels a bit sluggish but that could just be me not really knowing the car yet as I just got it. When I check to dme codes with mhd I get the following:

29CD- DME: Combustion misfires, cylinder 1.
2A17- DME: DMTL, system fault
2C40- DME: Oxygen sensor 2 before catalytic converter: Signal lines
2C9C- DME: Oxygen sensor heater before catalytic converter: Activation
2C9D- DME: Oxygen sensor heater 2 before catalytic converter: Activation
2C9E- DME: Oxygen sensor heater after catalytic converter: Activation
2C9F- DME: Oxygen sensor heater 2 after catalytic converter: Activation

Took the car to an independent mechanic shop in my area for an oil change and inspection. They told me that the plugs, coils, and o2 sensors are all in good shape. They think it's something to do with the wiring for the 02 sensor. They asked me if I wanted to leave it with them for another few hours but at 100$ an hour I figured I'd just try to figure out the problem on my own and come back.

Since the plugs, coils, and o2s are all good, what else could be causing the shuddering? What would be my best course of action here?

The car is completely stock btw. I plan to go FBO at some point but I want to get the care running well before I go down that road.

UPDATE:
swapped the 1 and 2 coils. coil 1 had lots of whiteish buildup inside it. blew most of it out with a compressor. i have no idea what the buildup was, if anyone knows anything about that i would really appreciate any insight. coil 3 was also a little loose, so i made sure all were seated properly and cleared the codes. went for a drive, cut it off, waited about a minute, and started it back up. the cel is back and the shuddering is still present but it seems so stop after a few minutes of running. checked the codes again and it the misfire is gone!! the other codes regarding the o2 sensor are still there so im thinking the shuddering must have to do with that.

if any of this means anything to anyone please let me know. im planning on replacing all coils and plugs soon so will update when thats done.

[Tunafish]

Have you cleared the codes and this is what pops back up?

[Ryan1963]

Probably should check if your coil packs are properly seated and clipped down all the way. If they are not, it will definitely cause a misfire eventually. While you’re at it, check condition of spark plugs.

[Schmitz]

I have a rough idle on warm start on my 328xi. No idea what's causing it. Changed plugs, and coils. Maybe it's the maf or solenoids?

[YungLawn]

Originally Posted by Tunafish

Have you cleared the codes and this is what pops back up?

cleared them yesterday and they came back almost immediately. just checked again and theyre all the same

[YungLawn]

Originally Posted by Schmitz

I have a rough idle on warm start on my 328xi. No idea what's causing it. Changed plugs, and coils. Maybe it's the maf or solenoids?

How would i go about checking the maf and solenoids?

[YungLawn]

Originally Posted by Ryan1963

Probably should check if your coil packs are properly seated and clipped down all the way. If they are not, it will definitely cause a misfire eventually. While you’re at it, check condition of spark plugs.

will hopefully have time to look under the hood this weekend. ill be sure to update my original post afterwards

[Schmitz]

Originally Posted by YungLawn

How would i go about checking the maf and solenoids?

No idea. That's why I haven't checked yet. My car isn't throwing any codes

[JonOhh]

My 06' 330i as well as our 16' 235i both do this. No idea what the cause is.

[Schmitz]

Originally Posted by JonOhh

My 06' 330i as well as our 16' 235i both do this. No idea what the cause is.

Maybe it just happens lol

[mousefarmer]

Have you checked your fuel pressure regulator below the back seat for cracks in the plastic or checked your fuel pressure? You may not have codes for this.