Any thoughts on why engine riding rough? - Page 2 - The Unofficial BMW M5 Messageboard (m5board.com)

Greybeast · 9th January 2007, 22:47

My SA got me in today on 45 minutes notice. Code read misfire cylinder#2. Their procedure on a one-time misfire fault is to swap the coil to another cylinder and see if it reoccurs. If it does, the coil will be replaced. As for the rough running, I was told that if a code is tripped, the car will stay in limp mode. As has already been stated, killing ignition and re-starting resets to normal. Mine actually resolved without doing that. Car is still running fine. I guess we'll see if it happens again. I guess it was worth the trip, as they also replaced a broken CD changer. Thanks for all the knowledge shared.

Texas · 9th January 2007, 22:53

Quote:

Originally Posted by Greybeast

On my way home from work this morning, my car suddenly began to run rough at about 50% power. The best way to explain it would be this:

I used to have a big block Chevelle whose #5 spark plug wire used to pop off the plug, leaving the car to run on 7 cylinders. This felt exactly the same.

The check engine light came on.

Whole thing lasted about 10 minutes then resolved and light is now off and car runs fine.

Thanks,

Greybeast

I had this problem, and it turned out to be an ignition coil. I had the same problem in my old Pontiac Grand am. It's a pretty common problem, but easily fixable.

maxm5 · 10th January 2007, 11:13

Yeah CPS replacement fixed the issue. Though the problem only lasted for 20 mins or so orginally. Has not re-occurred since replacement. Not sure which CPS was replaced. I think it was one which is more difficult to get to.

kcwrx02 · 10th January 2007, 19:55

Thanks for the reply back. mine seems to kick on over and over. After a few driving cycles it goes away, I get gas and everything is fine for a day or so, then I start romping around and usually kicks when I let off the gas or hit a bump...one of the errors said CPS ground fault or something like that before.
Maybe the connector is loose.

Quote:

Originally Posted by maxm5

Yeah CPS replacement fixed the issue. Though the problem only lasted for 20 mins or so orginally. Has not re-occurred since replacement. Not sure which CPS was replaced. I think it was one which is more difficult to get to.