E46 M3 idle issues....

[cjb211]

I have an 05 E46 M3 and was sitting at some traffic lights this weekend and out of the blue the RPM fell below the usual idle speed and almost stalled, although not quite. This happened a few times but has did not happen the following say... has this happened to anyone else?

I've also noticed that the car can be a bit juddery under acceleration lately (it's not the traction control)

anyone got any ideas as to what this could be?

It's still under warranty but only for a month!!

Also, had the diff oil changed under warranty the other week because teh dif was making a scraping sound... the sound went away for a while but now it's back!! any ideas on this? should i be trying to get a new one of them before the warranty runs out?

[Great Pretender]

Have any warning lights appeared?

Sounds like a sensor fault somewhere. Best get it booked in as something will have no doubt been logged on the ECU.

[darreni]

It sounds like it might be coils, they don't always trigger a dash light or fault code.
Just trial & error to replace.

[deano23]

cjb211 said:

I have an 05 E46 M3 and was sitting at some traffic lights this weekend and out of the blue the RPM fell below the usual idle speed and almost stalled, although not quite. This happened a few times but has did not happen the following say... has this happened to anyone else?

I've also noticed that the car can be a bit juddery under acceleration lately (it's not the traction control)

anyone got any ideas as to what this could be?

It's still under warranty but only for a month!!

Also, had the diff oil changed under warranty the other week because teh dif was making a scraping sound... the sound went away for a while but now it's back!! any ideas on this? should i be trying to get a new one of them before the warranty runs out?

Regards the juddering - mine can be like this sometimes under acceleration - particular from 2nd-3rd, and 3rd-4th. I've put this down to the tyres that are on it at the moment though (budget tyres). Can anyone confirm this maybe the case? Seems logical to me. What tyres are you running on yours by the way?

[Paul_M3]

Is it a BMW warranty?

If so, take it to them and explain all the symptoms.
Get it sorted as best you can while it's still under warranty.

[cjb211]

deano23 said:

cjb211 said:

I have an 05 E46 M3 and was sitting at some traffic lights this weekend and out of the blue the RPM fell below the usual idle speed and almost stalled, although not quite. This happened a few times but has did not happen the following say... has this happened to anyone else?

I've also noticed that the car can be a bit juddery under acceleration lately (it's not the traction control)

anyone got any ideas as to what this could be?

It's still under warranty but only for a month!!

Also, had the diff oil changed under warranty the other week because teh dif was making a scraping sound... the sound went away for a while but now it's back!! any ideas on this? should i be trying to get a new one of them before the warranty runs out?

Regards the juddering - mine can be like this sometimes under acceleration - particular from 2nd-3rd, and 3rd-4th. I've put this down to the tyres that are on it at the moment though (budget tyres). Can anyone confirm this maybe the case? Seems logical to me. What tyres are you running on yours by the way?

It not the tires, that's for sure. I'm have Contis

Booked it in at the dealer (BMW Warranty), will let you know the outcome...

[shim]

if as you say it is just poor idling and some sort of hesitation on acceleration (but no misfire) then i would look at replacing coils or maybe refurbing injectors or replacing plugs. (what mileage? - usually around 60k+)

if a misfire or bad running generally try pick up faults as it might be lamda sensor or others

[john_p]

Sounds a bit like what the M52TU does when the Vanos seals start wearing, hope it's nothing Vanos related. At least you have BMW Warranty.

[cjb211]

it's only done 32,000 miles so i don't suppose i'll have to have much of an argument to get BMW to fix it should there be a major problem...