2008 528I with 88k miles. When I gas the car i feel a shudder around 2000rpm-2500 rpm. If I gas it hard the CEL will come on and but then it'll go away after i continue to drive ?

if I drive and accelerate lightly there is no shudder or CEL

From what I gathered is that it could be o2 sensor, bad coil ?

Anybody with the similar issue? what was the solution?

im going to fill up with shell gas after work today to see if it helps. and ill try to gas it so i can get the CEL to come back and get it scanned.

 

Given the check-engine light is coming on, read the diagnostic codes. Those codes will lead in the direction of root cause.

 

The cel came on and stayed on this time. Went to autozone and got P0304 misfire cylinder 4.

 

I would install new plugs and swap the #4 coil it another one to see if the misfire moves. Most likely, the plugs will take care of this.

 

yea, order the coil....how often do you change your plugs? bought my car at 60k miles its at 87k now.. I haven't changed it..im pretty sure the previous owner hasn't either

 

My car has 140K miles with original ignition coils. I bought a set of new ignition coils; will replace them when I see a hint of any ignition related issues.

 

wow i've replaced one of them already about a month ago...

the CEL wasn't on when I left for work this morning...still feel the shudder.... does the CEL come in and out when the coil is bad?

 

Ignition coil can degrade [due to age and temps] and cause those symptoms. If the degradation is borderline, the symptoms can be seen [with the associated CEL light] when driven hard or driven in humid weather.

 

When you have a misfire, whether from coil or plug causes, the CEL will flash while it misfires if the misfire lasts more than a second or so. The emissions rules require this in North America but I believe they do this in all catalyst equipped markets as the cats are easily ruined by raw fuel.
If the misfire is too brief it will not flash. In either case the CEL is on for a bit and when no more misfire it goes out but leaves a code for a few dozen warm up cycles if no more misfires are detected.