[Jonnyweninger]

• Hey guys, in here again. can’t get my car to go into high boost without a misfire on a random cylinder it picks. replaced lpfp sensor clearly not the issue. issue is else where but i don’t think that’s why i’m having these issues. i see both pre cat o2s are not working. would that possibly cause a misfire when i start to boost. it’s targeting 20.2 psi but gets to around 11-13 psi before it cuts and hesitates really hard. Yes coils and plugs were changed before i flashed to stage2+. running fmic upgrade and catless dps. for the stage 2. plugs were gapped to .022 and eldor coils installed. i’ve quadruple checked everything. i guess i’m going to replace all o2s cause i may as well and see where that gets me. according to my tuner i have a leaky injector which i know is cylinder 3 but most of the time thr misfire codes i get are not for cylinder 3. my afrs are super lean at 15.11 wot. any help would be great. 08 335i 97000 miles

[mikelord7]

I’m having a similar issue. Replaced plugs and coils. Was running fine for a few days but now misfiring again.

Going to try a few things this weekend and will let you know if anything works. Please update your post if you figure it out first.

[Jonnyweninger]

Originally Posted by mikelord7

I’m having a similar issue. Replaced plugs and coils. Was running fine for a few days but now misfiring again.

Going to try a few things this weekend and will let you know if anything works. Please update your post if you figure it out first.

just ordered fresh o2 sensors. both my pre cat sensors are done which in turn messing with my fuel trims. i’m super super lean at 15.11/1 afr which is not good at all. if you have any o2 sensors i would replace. also check your injectors out make sure they are not leaky

[Jonnyweninger]

Originally Posted by mikelord7

I’m having a similar issue. Replaced plugs and coils. Was running fine for a few days but now misfiring again.

Going to try a few things this weekend and will let you know if anything works. Please update your post if you figure it out first.

Hey just wanted to reach back out to you. After doing testing and changing the tunes on the car. i noticed that with my both pre cat o2s the car runs okay. on a base tune. can only run it on mhd stage 0. any other tune car falls flat on its face. so for now i’m leaving them unplugged until i get new o2s which they should be here this week hopefully. been testing back and fourth and it seems the only way to get it to drive is to like i said have them unplugged and on a base tune. running the car with them unplugged won’t hurt too much car runs off iats instead. anyways that’s what i found so far otherwise i got nothing. after i do the o2s and it doesn’t work i’ll just be replacing all my injectors

[whyzee125]

You have two known hardware issues and are running lean. Fix those asap or you risk damaging your engine. I’d certainly think between those two it will cause a misfire so they should clear it up or at least point you in the direction of the final missing piece.

[mikelord7]

Thanks for following up. I scanned my car again and my misfire is now cylinder 6, was cylinder 2 before i replaced coil pack.

Also now getting boost pressure sensor errors? Going to try new MAP sensor on the intake manifold. Hoping this is it but no clue. If not, gonna need to chase the misfire another way.

[Jonnyweninger]

Originally Posted by mikelord7

Thanks for following up. I scanned my car again and my misfire is now cylinder 6, was cylinder 2 before i replaced coil pack.

Also now getting boost pressure sensor errors? Going to try new MAP sensor on the intake manifold. Hoping this is it but no clue. If not, gonna need to chase the misfire another way.

Yes replace the map sensor. also make sure you installed your charge pipe properly. i had the same issue ran like shit on startups and turns out i was missing thr oring inside the charge pipe that connects to the throttle body. if plugs and coils didn’t fix your issue next step would be check the injectors & compression test unfortunately yes it’s possible you have low compression. generally on these cars it’s cylinders 3&4 that are weak points