[Andrew2512]

Hi guys,

I had a bad plug a month ago, cyclinder 2, but I replaced all of them with Bosch OEM, I also found out that my #4 coil was also broken so replaced that as well.

And now after a month the car shakes on the highway no matter what the speed it, idle is rough. Shakes for a second when stopped in traffic and I don’t have any codes on the dash.

Should I push the car a bit for it to throw a code.
The car also doesn’t sound good at all.
CAR IS STOCK

TIA

[LuxoM3]

Probably another coil - people tend to replace all 6 of them versus just one or 2.

[Andrew2512]

Should I replace all the coils and then wait for it shake, or wait of the code to show up before doing anything ?

[LA430]

Read codes, find misfiring cylinder, move coil to different cylinder, see if misfire follows.

Parts canon can cost a lot of money.

[Andrew2512]

How do I find the misfire, no CEL, should I push the car ?

[LA430]

Do you have any kind of flashing device or code reader? You’ll need to check live data. I use BimmerLink to check live misfires.

[fe7565]

I bet if using ISTA+ it will show some hidden (BMW specific) codes that can clue you in to the source. You can buy a $10 ENET cable on Ebay/Amazon and there is a thread on ISTA+ download.

[Andrew2512]

I have bimmerlink how do I check live misfire ?

[LuxoM3]

If you REALLY want to keep testing and you don't have a reader the easiest way is to just unplug a coil and start the car, no change... make note, reconnect and move to the next one.

With a good coil, the unplug will dramatically affect the car - sputters, shutters, chokes, etc. With a bad coil, nothing will happen... and that's the bad one.

Coils aren't known to last forever. My son got 145k out of his 328i/E90 coils before the car started choking, stalling, stumbling. Replaced, problem solved. I'm at 81k on my 435i. Still going but have a set just in case.

I advocate replacing all 6 versus one simply because, the other 5 WILL fail at some point.

[Andrew2512]

I found the misfire, cylinder 4, replaced the spark plugs and coil and it’s still misfiring like crazy now it’s misfiring even more.

[thejeremyman9]

Originally Posted by Andrew2512

I found the misfire, cylinder 4, replaced the spark plugs and coil and it’s still misfiring like crazy now it’s misfiring even more.

Replaced all of them?

If you made it worse by replacing plugs/coils you probably cracked a plug on install or damaged a coil...

You need a code reader as mentioned above. CEL and "codes on the dash" are totally different than connecting to OBD

[Andrew2512]

I connected the car with the reader that’s how I found out it was CYlinder 4.

[LuxoM3]

So where's the misfire now based on the code read?
Silly idea... did you make sure the coil is pushed all the way down onto the plug?
So it makes a snap/pop/click sound? I worked on my 435i once, changed out all the plug and the car misfired like crazy. Turned out, I didn't push one of the coils all the way down.

[E36M3]

Are you using a torque wrench when installing plugs? If so what are you torquing them to? I had a similar issue before I started using a torque wrench. The thin wall plugs crack the porcelain if overtorqued.