[trystan_e90]

Alright so i drive an 09 e90 335i that is FBO. I run jb4, ar downpipes, hpf fmic, er chargepipe with hks bov, and a vanguard v2 exhaust. I also just recently did the bms backend flash.
I was getting the 2c9c code, so to my understanding that meant i needed to replace my driver side pre-cat o2 sensor. I just replaced my sensor yesterday and i am still getting the code. My biggest problem is that at WOT sometimes, the engine starts getting shaky and clunks, and re-pops my CEL. I'm not sure why this keeps happening. After about 10-15 seconds, the car goes back to driving normal again. The car runs really good besides when i'm going WOT. I'm not throwing any other codes. Anybody have any ideas? It would be greatly appreciated, thanks!

And just for clarity, i was getting the WOT problems and the 2c9c code, and that is why i replaced the o2 sensor, thinking that would solve my problem. And it hasn't so i'm really not sure what the problem is.

[diegopiedra]

U either have a boost leak causing ur car to run rich and ur o2 sensors will read that or ur spark plugs are bad

[trystan_e90]

Spark plugs were just changed 1k miles ago. And i don't think i have a boost leak because i still peak at the same PSI as i was.

[Jeef]

Originally Posted by trystan_e90

Spark plugs were just changed 1k miles ago. And i don't think i have a boost leak because i still peak at the same PSI as i was.

Coils?

[trystan_e90]

Would bad coil packs throw a code?

[thestein1016]

Originally Posted by trystan_e90

Alright so i drive an 09 e90 335i that is FBO. I run jb4, ar downpipes, hpf fmic, er chargepipe with hks bov, and a vanguard v2 exhaust. I also just recently did the bms backend flash.
I was getting the 2c9c code, so to my understanding that meant i needed to replace my driver side pre-cat o2 sensor. I just replaced my sensor yesterday and i am still getting the code. My biggest problem is that at WOT sometimes, the engine starts getting shaky and clunks, and re-pops my CEL. I'm not sure why this keeps happening. After about 10-15 seconds, the car goes back to driving normal again. The car runs really good besides when i'm going WOT. I'm not throwing any other codes. Anybody have any ideas? It would be greatly appreciated, thanks!

And just for clarity, i was getting the WOT problems and the 2c9c code, and that is why i replaced the o2 sensor, thinking that would solve my problem. And it hasn't so i'm really not sure what the problem is.

Are your ars catted or non?

[trystan_e90]

Originally Posted by thestein1016

Are your ars catted or non?

They are catless.