[halfmonkey]

My car is starting to misfire or something. The car hasn't shown any service engine lights but it sure feels like a misfire. The car currently has 115k and the spark plugs were replaced at about 95k miles. I've had various injectors and ignition coils replaced under warranty and extended warranty so I can't remember the last time one of the injector or coils were replaced. I'm thinking the injectors are going bad.

I'm getting the hesitation/misfire while under load especially when I'm not pushing the car hard enough to force it to downshift but still putting a load on the car to accelerate.

This will be coming out of my pocket. Does anybody know how much it is to replace injectors?

So another question I have is regarding carbon build up and how this affects the injectors. I just tried buying a little bottle of the Lucas Oil fuel injector cleaner and poured it in. I can't imagine it's going to work an overnight miracle but if it helps "clean" the system, it's worth a try.

Does anybody regularly use these cleaner fluids?

Has anybody actually gone to the dealer to have them clean out the engine for carbon build up? If so, how much did they charge you for this? Did they actually do something or just pour in some techron?

[buly34]

I bought my 335xi at 111k and the first ride home I floored it on the highway in 5th gear and got a misfire, but it fixed itself after about 30 seconds and never happened again. At the time I had no idea what it was, and thought it was just a once and done issue. I went on to install a JB4, DCI, and DP's. With the tune on I couldn't give it more than 3/4 throttle or it would misfire until I cleared the codes via JB4 in dash settings. It gave me a misfire in only cylinder one multiple times so I replaced the plug. Then I got misfires in 4 and 6

I spoke to my buddy who works a BMW stealership and he mentioned the carbon cleaning, which would cost $1,200. I wasn't about to pay that so I bought a kit and did it myself. Here are the results from Cylinder 2...




I noticed a big increase in response at start up. Did a hard pull andddddddd misfire...So I did all the plugs



After all that my car pulls like a rocket and has no more misfires. Dyno'd at 344whp and 380tq

Don't waste money on cleaning fluids, because these cars are direct injection they have carbon build up. Unlike a non DI car where the fuel cleans the valves out, our cars do not. Do the carbon cleaning and change your plugs before replacing injectors. It will be much cheaper and even if it doesn't fix the issue it most likely needs to be done.

Here is the kit I used, don't forget to buy intake and throttle body gaskets.

Bavarian Part Number: B1100001

DIY: http://blog.bavauto.com/15543/

Hope this helps!

[BashShah]

Do a Walnut blast before anything else.

OP, when I first got my car, I had the exact same issue.
Jerking hesitation under light throttle.

Walnut blast man.....you will see a day and night in performance.

DN