[intothecocytus]

I've been having this issue for a little while now after letting my bmw sit for half a year waiting on a repair. I've driven it to a from work for about a month now to see if it was a fuel issue (fuel sat in it but i used an additive but have refueled a handful of times since) but the engine is still shaking and stuttering RPMs while idle and at speeds below 30 MPH.

I get a rough back and forth shake while going downhill every so often and a slight shake seldom when i take my foot off the gas and let it coast to a slow speed.

Before it sat it had gotten a tune up a few months prior and had the head gaskets replaced and oil change and all that and repair places it's gone to aren't really sure what's wrong with it. My wife has taken it to several places while I'm at work so I'm not sure if it went to a BMW service center.

Has anyone had an issue like this and had it fixed that could give some advice on what could be wrong? I've done some searching on google and youtube since I don't know much about car repairs (ive been a youtube mechanic recently lol) but can't find anything definitive.

It's gone through a driveshaft replacement and a tear in the transmission casing(?) or whatever it's called that just needed to be patched up and didn't cause irreparable damage.
It's at around 166k miles

Any kind of insight would be greatly appreciated!
The year is 2016**

[TheCoolX3]

Check plugs and coils, thats going to be the easiest to begin diagnosis.

With the car cold, grab the engine and try to shake it in all plains. That will test your motor mounts.

After those i'd look into getting injectors tested/checked/replaced.

Any odd nosies coming from the timing cover/belts?

[intothecocytus]

I checked the coil packs and they seem fine. Any engine shake techniques or just grab it by hand and try to shake it? What exactly should I be feeling for while shaking?

I forgot to note that my check engine light has been on throughout this issue as well.

[intothecocytus]

I hear some popping coming out from the airbox while it's idle. I'm not sure what kind of sound would be coming from the timing cover or belt. I hear something like valves smacking

[94vtirozguy]

could be the timing chain issue, o2 sensor gone, cat gone....