Whole car shakes under power after tune - Blinking engine light

[Exactly]

Hi everyone,

Thanks for taking a look at my first post. Updating my profile after this =)

I recently got a tune put on my 2009 335i coupe w/ 70k miles after a year of it running flawlessly stock. It has Bilstein shocks with H&R lowering springs and drove wonderfully. I had full bolt-ons installed recently (larger VRSF inlets that are a pain to install have been ordered and will be installed soon) by a performance shop in my area who also did the custom tune. The day I picked the car up, I noticed a very rough idle. At stop signs, the car would shake pretty bad. Honestly was hard to get power out of the car which I found odd since it felt faster before and I was supposed to gain a lot of power. When I would get power, the car would sometimes shake really bad when accelerating.. steering wheel, dash, everything shakes bad).

Cold starts, and really any time I'd start the car it would literally sound cammed and shake (If you want a video let me know). I honestly thought all of these problems I was having were supposed to happen because of the tune. Remember, I am used to a stock 335i that drives nice and smooth with instant power. The car felt like it was clearly not running right so a few days ago I scheduled an appointment with the shop to get it diagnosed but they can only work on it on 7/30/21. Long story short, I was driving home today, and the car felt extremely slow. Getting the car to get up and move was difficult, almost like I had to fight it. The shaking when accelerating was very bad today, and under even normal power it was shaking every now and then. I then noticed my check engine like was flashing. Pulled over, and stopped the car and called the performance shop and they said get it towed here, but the tow was going to be very expensive so I kept the car off for 15 minutes, turned it back on and drove home with no flashing engine light. The shop is going to look at it tomorrow in the morning.

Does anyone have any ideas for what is happening before I drive it to the shop tomorrow? Should I NOT drive it and get it towed? Am I an idiot for driving it home? I guess you will all let me know. I think my car has been misfiring since I picked it up from the shop 2 weeks ago but I have been driving on it ever since which thinking about it now sounds like it was a bad idea. Either that, or I need new spark plugs, coils, or injectors. Also, my solenoids could be shot but I religiously change my oil. Never got engine reduced power, just flashing engine light.

I appreciate y'all

[zellamay]

They delivered the car to you like this? That's ridiculous. Get them to haul it to their shop and fix the problem. I wouldn't drive it without knowing what is going on. It could be that they put something back together wrong, or that the tune is crap. Either way, it's on them.

[mbonder]

Sounds like their custom tune was a pile of garbage. If they delivered it to you without test driving the car to confirm that it ran better than when you dropped it off to them that's another red flag. Sounds like your performance shop isn't that great. I'd ask them to flash it back to stock and then take it somewhere with a reputation to back up their work.

[Exactly]

They delivered the car to you like this? That's ridiculous. Get them to haul it to their shop and fix the problem. I wouldn't drive it without knowing what is going on. It could be that they put something back together wrong, or that the tune is crap. Either way, it's on them.

It's been running like this since I got the tune put on. Yesterday when my check engine light was flashing was the last straw. They told me they datalogged it and it ran fine. I ended up driving it to the shop today, and boy did it feel like I was running on 2 cylinders. I could hardly keep up with the slowest semi truck on the freeway.



Sounds like their custom tune was a pile of garbage. If they delivered it to you without test driving the car to confirm that it ran better than when you dropped it off to them that's another red flag. Sounds like your performance shop isn't that great. I'd ask them to flash it back to stock and then take it somewhere with a reputation to back up their work.
They told me they datalogged it, and we both joked on the phone when he called me to pick it up that it's been such a reliable BMW. The crazy part is this shop is very reputable, everybody takes their cars here. People sometimes drive 8 hours to get to the shop but I live 30 mins from it and work 30 seconds from it. I am really confused as to what happened with this tune with that being said.. It's at the shop now, but they didn't look at it today. I am working remote since I don't have a car and it'll probably be a while til I get it back.

[mbonder]

They should have physically test driven the car. Datalogging it is bullshit as it doesn't put the car under the actual various stresses of being on the road, plus it doesn't give the car enough miles for the computer to adapt to the new maps and whatnot.

Insist on the car being test driven for several miles after they figure out what is going on, not doing so is pure laziness on their part and should not be accepted.

[Exactly]

They should have physically test driven the car. Datalogging it is bullshit as it doesn't put the car under the actual various stresses of being on the road, plus it doesn't give the car enough miles for the computer to adapt to the new maps and whatnot.

Insist on the car being test driven for several miles after they figure out what is going on, not doing so is pure laziness on their part and should not be accepted.

I took the car back on Tuesday and just got it back today. They replaced all of my sparks plugs with NGK 1step colders, I had 4 very burnt plugs. They also swapped out my coils with brand new ones because I had a misfire on FOUR cylinders. The car drives perfect now. They dialed in the tune more and I couldn't be more happy. It takes off like a rocket with no effort, I must be pushing sub 400 horsepower.

All in all I am not sure who's fault that was but I am glad it is over.

[zellamay]

I know the feeling: just glad it's over. Still, two thoughts; first, they never should have returned the car to you like that. Second, they should have known, or at least checked, about the plugs and coils with the tune. What did you pay, for everything?

[Exactly]

I know the feeling: just glad it's over. Still, two thoughts; first, they never should have returned the car to you like that. Second, they should have known, or at least checked, about the plugs and coils with the tune. What did you pay, for everything?
I'm also confused as to how they returned the car to me like that. It felt ROUGH when I picked it up compared to now. It actually feels pretty close to stock until you want power. Thankfully, they didn't make me pay for labor, just for the coils and plugs. They must have realized they were supposed to check those.

[JDStrickland]

Sorry, I'm missing something. You spent thousands on service and the car ran poorly afterwards, now you are asking the internet for guidance? Take the car back to the place where it was broken.