BMW 4 Series Convertible problems with misfiring for some time now

Smokers will be smoking you know

Hello ! I currently own a 2005 BMW 325i e90. I have a valvetronic problem that was detected before the summer but the BMW garage did not change it because for them "not critical". Today I had an incident on the freeway when I got to the toll booth. I didn't downshift enough and accelerated into 4th gear at 40km/h. The car started to jam. The car then started to graze and it was impossible to exceed 60km/h with a small yellow engine light... I stopped on the side of the road, restarted the car and everything went back to normal. I was able to finish my journey and return home afterwards (3h30 of driving) without a hitch. Being concerned, I started using my Carly bag to check... and now it's not even giving me the valvetronic error, it's giving me error code 0029D2 "failed to start, cylinder 6" with the "react immediately" + another error code concerning the Vanos "be careful". I'm going to call BMW on Monday to make an appointment, but I wanted to get the opinion of one of your mechanics. Should I immobilize the vehicle? Knowing that I drove without problem more than 3 hours after the problem?

(Translated from French)

Based on the error codes you've provided, it seems like there might be an issue with the ignition or fuel system in cylinder 6, as well as a potential issue with the VANOS system. While it's possible to drive with these issues, it could potentially cause further damage to the engine. I would recommend not driving the vehicle until it can be inspected by a mechanic. It's always better to be safe, especially when it comes to potential engine issues. Please keep us updated on your progress.

My bmw e93 (N43b20a) around 95,000 miles has been running very rough recently with some smoke coming out. i have replaced injectors and coil packs but the car feels extremely down on power.

If you're still experiencing power loss and smoke even after replacing the injectors and coil packs, it could be a problem with the turbocharger, if your car is equipped with one. A failing turbocharger can cause a significant loss of power and produce smoke. Alternatively, it could be an issue with the exhaust system or a clogged air filter. I would recommend checking these components next. If the problem persists, it might be best to have a mechanic inspect your vehicle. Please keep us updated on your progress.

Hello Spark plugs and coils are all new what can it be ?

(Translated from German)

If you're still experiencing issues after replacing the spark plugs and coils, it could be a variety of things. It could be a fuel delivery issue, such as a clogged fuel injector or a failing fuel pump. It could also be a sensor issue, such as a faulty Mass Air Flow (MAF) sensor or Oxygen (O2) sensor. I would recommend checking these components next. If the problem persists, it might be best to have a mechanic inspect your vehicle. Please keep us updated on your progress.

Hi guys, Yesterday i’ve changed one of the injectors on a bmw e87 120i n43b20a 2007, after getting misfire on cylinder 4. Coils and spark plugs have been changed half year ago. (it’s the 3rd injector i’m changing in the last 2 years, since I got the car). Today it was running really smooth, no more jerking, no more misfires. After a 40 minutes drive, when I stopped in a parking lot, it started trembling and got the orange check engine. (misfire on cylinder 4) cleared the error and it went away, drove for about 1h and no more misfires, it started running smooth again. I’ve changed lambda sensors as well one year ago and MAF sensor. Could there be a vacuum leak that causes the misfire and the injectors could be fine? I’m checking for vacuum leak with a smoke machine tomorrow to see if there is any leak… what other issues could cause misfires apart from coils, spark plugs, bad cables, injectors? Thank you!

It's good that you're checking for a vacuum leak, as this could indeed cause misfires. Other potential causes could be a faulty fuel pump, a clogged fuel filter, or issues with the engine control unit (ECU). It's also possible that there's a mechanical issue with the engine itself, such as a worn camshaft or timing chain. If the smoke test doesn't reveal any vacuum leaks, I would recommend having these components checked next. Please keep us updated on your progress.

Thank you very much for your fast reply. The ECU is definitely working fine. Shouldn’t there be a code for the fuel pump if there was an issue with it? I’ll also check everything you mentioned and replace the fuel filter as it was never changed. I think it’s somewhere hard to reach and bmw says it’s lifetime on gasoline cars.