Hi, I’m writing on here to try to figure out what’s wrong with my car. I got a 2008 bmw 535xi with about 140,000 miles on it. Recently the car has been idling very rough, so I changed spark plugs. Old spark plugs were dry and black. After I changed the spark plugs, the next day went to give it a cold start and engine started misfiring on cylinder 1,2,3. Thick white smoke came out of exhaust with strong smell of gasoline. Next day gave it a cold start and engine started misfiring, but stopped as I started revving the engine lightly. When I drive the car white smoke goes away, but when idling it return. Very rough idle. Misfires occur only on cylinders 1,2 and 3 Could this be bad coils? Any help would be great thanks.

 

You need to check the codes on the car. Once you get the codes and post them. We should be able to help then.

 

 

What plugs did you put in? If they are not the OEMs replace them. Did you make sure the coils were all the way down on the plugs and plugged in. If you are sure of the 2 then switch the coils to the other side to see if the misfires follow the coils (this will let you know if it's the coils).

How old is the battery? Make sure your battery is charged if it's not an old battery. If it is old have it checked to make sure it's till good.

The above should take care of the cheaper routes. Once done report back on your findings.