KOAN 0 Report post Posted July 8, 2014 Hi folks, I own an 04 645ci (around 102k km) and am having some issues. First off I have got it booked in next week at my BMW specialist, however, it's symptoms have gotten worse and was wondering if anyone has any ideas. Catalytic Converters I'm getting a warning message saying that my there's an engine fault and that "high loads can cause damage to catalytic converters". It is accompanied by the yellow engine warning light - this has not shut off since happening around 12 pm today. On cold mornings when I'd start my car, I would get this message, but would soon disappear and have no warning light. I have recently changed the air filter to a K&N as the last filter was quite dirty. Rough Idling and Vibrating For the last week or so, it had been rough idling in the morning on a cold engine start. And the revs were going up and down and a few mornings would just stop completely, right after turning it on. Since today's messages and warning light the car has been roughly idling and vibrating heavy when I take my foot of the brake, and feels like it's grinding almost when I'm accelerating. I can every feel it vibrating quite bad behind the pedals and foot rest. Also, my fuel consumption seems really high as it says 16.4L per 100km and feels like it's chewing through the gas (95) Could the Catalytic Converters be on their way out? I haven't checked spark plugs, but I know they are due for replacement. Any advice would be much appreciated as I am concerned about driving the car in this state. Quote Share this post Link to post Share on other sites
qube 3568 Report post Posted July 8, 2014 check spark plugs! Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted July 8, 2014 Sounds like a misfire. Which can damage the cats hence the.warning. The code scan should tell whats wrong pretty easy. Quote Share this post Link to post Share on other sites
Allanw 1051 Report post Posted July 8, 2014 ^ he beat me to it. Code will probably be for a misfire - either dodgy plugs, coil pack etc... probably not to dramatic, but I'd take it easy, or not drive it until it's sorted. Quote Share this post Link to post Share on other sites
turbolizard 38 Report post Posted July 8, 2014 Given that you have just put in a K&N filter then I would check that your air mass flow sensor is not covered in oil. Overall, I reckon a new paper element filter is a better proposition. Quote Share this post Link to post Share on other sites
