[cat97628]

I am having a bit of an issue when I punch the gas to merge into traffic or just want to have a bit of fun. I get a check engine light and then the car starts running like crap with even moderate to light acceleration. If i come to a red light i can feel the engine struggling and the RPMs are all over the place. I can pull over and shut the car off and restart with no problems at all. I can drive for hundreds of miles without having the problem until I really punch the gas. The car has 115k miles and had both VANOS were replaced at 100k. I know I need an oil change and will be doing that this week. Any ideas where to begin to look?

Thanks

[BostonPoke]

Cylinder misfires?

[cat97628]

it seems like a misfire but what would cause it. Maybe ignition coils and plugs?

[drunkenup]

Also maybe injectors or carbon buildup. I got an ses light and misfires after trying to WOT once, no iDrive message though. Need to pull codes

[bimmerben335i]

Injectors, coils, plugs. I would change plugs first. If that doesn't help then I would proceed to changing all 6 injectors and coils. Also I would get your intakes walnut blasted. Heck of a difference it makes. You'll have power you never thought you had. Just my .02 considering I just sent through this a month ago.

[Art818]

Usually what you do is read what cylinders it says is misfiring then swap ignition coils over and see if it moves if it doesnt its your sparkplugs if it does its your ignition coil if its none of those it might be your injectors? worst case scenario its your intake valves which is going to need Walnut blasting

[924er]

guys he's driving a 328i its port injection. no carbon build up.

it sounds like a misfire, you need a code reader to really help narrow it down.
european cars are notorious for misfires.
start with plugs/coils/injector/

good luck

[Patel511]

Coils AND plugs.

[Victor328i]

Throttle body sticking? Happened to me, had to get a new one, luckily it was under warranty

[Morpheus]

plugs

[e90DJ]

had this same problem. First time in the dealership i got a carbon cleaning, after that the car ran just like before. But, 2 weeks later the same problem occurred, but worse. Turned out I needed 6 new fuel injectors. The dealership covered all but $200 of the repair.

[e90DJ]

wait, i have a 335. disregard that

[SSW]

I had the same problem develop recently too. Had the intake valves walnut blasted and replaced all of the plugs and coils, which were all due to be done anyway, and the problem went away.

If you want to try to "diagnose" the problem, start w/the coils. Your CEL code reader should tell you which cylinder(s) were misfiring. Then switch the coil(s) from the misfiring cylinder(s) to non-misfiring cylinders. Then run it again til you get another CEL and, if the misfiring occurs in the different cylinders, you'll know which coil(s) to replace.

If there is no change in the misfiring pattern, then it could be the plugs. You can change the plug(s) in the misfiring cylinder(s) or change them all to see if the problem goes away. Since you don't have a 335i turbo, walnut cleaning the intakes probably doesn't apply.

So, if changing your plugs doesn't work, then it's probably your injectors and, you will probably need a qualified shop to fix the problem because I believe the injectors have to be "coded" when replaced.

Good luck!