Hey, Im a new guy on here and I need some help. I have a 545i which is kind of shaking when idling. Seems like a missfire but no codes. Also I noticed that the RPM's are kind of low (500) but the might be normal? Another thing is that I just recently bought aftermarket M5 18' wheels with falken t22 tires, at around highway speeds the car has a vibration? might not be balanced correctly?

 

Welcome. I also have a 545i, so here is my opinion (right or wrong):
1. My car does not have a perfect idle. A little rough, but does not really shake the car. I believe this is somewhat normal for the valvetronic engine, but not sure. 500 rpm may be 50 to 100 low, but basically normal. Depends on A/C on or off.
2. The vibration at highway speed is a problem for many and I have not seen anyone come up with a cause and/or solution. The vibration can be caused from many things, so for sure ensure that the wheel/tire assembly is properly balanced. My car does the same thing and I have not been able to solve the issue. The vibration on my car comes adn goes rhythmically.

 

Alright Thanks, yeah the idle is not that bad might just be the big N62

 

Make sure that you have hub centric rings on your rims. When you mount your rims, the rim sits on the top of the hub and the bottom might not sit flush to the hub. So now the rim is not centered on the hub, which will cause an annoying vibration. The hub centric rings will correct that. Take your car to a "GOOD" rim shop and they will get you the right fitment for your wheels. It cost about $15-$20 for a set of 4. Hope that helps.

 

Try a bottle of Techron fuel additive. If it dirty valves $6 might clean it up.

I had a similar idle problem where RPMs would be around 500, then dip to 375 or 400 and the engine would stumble, then return to 500 rpm. I paid an indie $100 for what I later discovered a bottle of Techron could do.

RE: Road Vibration
If the car road smoothly before the wheel/tire change that pretty much narrows it down.
Have the tire center try balancing the wheels/tires.