Power loss - 2012 135i 6MT - Help?

[Chicness]

As of today, after much diligence, I concede that this car is a brick. This post is a long one, but it’s a good read. You’re gonna laugh. I’m crying.

2012 135i 6MT M-Sport
Purchased new - no modifications
11,600 miles

The car has no throttle response, no guts but will drive decently if I gas it just right - but obviously that’s not what it should drive like. This started a couple years back, initially just being weirdly sluggish at weird stages of the powerband, but because of financial reasons I just haven’t been able to take it in.

Carly OBD in hand (with app unlocked).

I’m not a bad mechanic but I’ve now managed to have it be sluggish in a totally different way...

Initial issue:

I was on the expressway and started to feel a loss of torque in the 3K to 4K+ RPM. It would be just fine, hit 3K, and just rev up smoothly to somewhere above 4K without there being any pull.

And then BAM! the thing would take off like a rocket. Super alarming, super dangerous and of course I immediately got a speeding ticket.

At the time I thought it was a vacuum leak and that the sudden gain in power was due to the RPMs being high enough to overcome it, but I have only worked on carbureted cars and motorbikes.

I should add that my battery was dying at the time. The “Increased Battery Discharge” warning light would greet me every time I started the engine.

So I just stopped driving it. Unfortunately I have to park it on the street in New York City and it is eating me out of house and home. Yes, I should have taken it to my shop, but (I bought this car new) that shop is BMW of Manhattan and no longer under warranty.

What work I’ve done lately

Lately I’ve been working on it as the battery became non responsive. In order to code the battery I bought a Carly, paid for the current app and installed.

But it was super dead when Covid hit and wasn’t driven for months before I got the battery (freakin’ pandemic). The computer was not happy.

Starts fine. Filled it up with Premium 93 (always premium 93).

I still had that weird power then no power with RPMs then super power.

Carly gave me a misfire/short in cylinder 4 and I replaced the ignition coil. Cleared the codes and it hasn’t come back.

In fact, I’ve replaced all the ignition coils, the spark plugs, the oil, run diagnostics and engine health over and over via Carly. Additionally, I’ve examined the heck out of everything and nothing is obviously out of sorts.

Two things:

The power loss is across the powerband now. I can wind it up, but it’s like pushing rope. Gutless. Reminds me of driving my V6 1974 Mustang in school. Worse.

I can’t get it legal to park on the street because the emissions systems aren’t ready.

I’m not generating any codes.

Searching this forum produces a lot of similar stories and they’ve been helpful, but I can’t find a solution.

Help.
Help?

To recap:

Car sucks to drive.
No codes from Carly recently.
Pushing rope.

Thank you in advance. Super rough year and this has been such an incrementally expensive issue that I cannot feed anymore.

Thank you in advance.

(Can’t I just reset it?)

[Petro135]

Sorry to hear. It could be alot of things, fuel pump, injectors, maybe dirty vanos. You have to get it diagnosed. Theres a place in Queens called m-spec or m-sport dont remember exactly. But i met a fellow 1er that swares by them. Might want to check it out. At least if you bring it there for diagnosis you wont have to pay for parking for a couple days

[tracer bullet]

Agreed, time to take it somewhere that knows the cars and how to diagnose them.

Hope it works out OK.