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GoSlow2GoFast
05-07-2005, 07:07 PM
I have an '04 M3 with about 21,000 miles. Every so often when cruising along at steady speed a very small skip can be felt, sort of like if one cylinder didn't fire for one cycle. It's very minor, most people don't even feel. But I do. Not big enough to really affect driveabilty or performance, and only happens once in a while.

Just wondering if any other owners have experienced this, and have any light to shed. I'm sure the dealer would laugh at me, it's that small, and I really don't want the tech driving the car around for an hour trying to feel it.

~bill

Pinecone
05-08-2005, 06:32 PM
Take it in. There could be a problem with a coil pack or with the coil to plug connector. Also cam position sensor can give something like this.

Just tell them what is happening, and let them try to figure it ou. Keep taking it back until it is right.

HUMMM 3
05-22-2005, 09:24 AM
Take it in. There could be a problem with a coil pack or with the coil to plug connector. Also cam position sensor can give something like this.

Just tell them what is happening, and let them try to figure it ou. Keep taking it back until it is right.

Would a "skip" like this generate a fault code? :dunno:

Pinecone
05-23-2005, 10:54 AM
It may or may not.

dawgbone
05-23-2005, 11:04 AM
Would a "skip" like this generate a fault code? :dunno:
Most codes won't flash until you see check engine/service engine light up..Any other code that would flash would reset every time you start your car...Mine has done something similar since I picked up the car, but only at idle, never under a load..I know that it is too inconsistant for a tech to find anything..So I'll wait till something breaks or it starts predictably doing it...I did tell the service tech, and he kinda gave me a :dunno: ..But at least he knows...

bol
05-23-2005, 11:52 AM
Most codes won't flash until you see check engine/service engine light up..Any other code that would flash would reset every time you start your car.

Not true, only certain categories or severity of a code will light the check engine light, there still may be codes in the ecu.

dawgbone
05-23-2005, 12:40 PM
Not true, only certain categories or severity of a code will light the check engine light, there still may be codes in the ecu.

Sorry...should have been a little more descriptive..And the point you've made was what I was trying to get at..As I said "MOST" codes are resetable, meaning no scanner is needed to erase the code. If the code is not "severe" enough to trigger check engine, then odds are that you will never see it flash. It's basically an I/O thing for the ECU to react to, and has nothing to do with diagnostics..And can easily be reset by shutting down the car and allowing ample time for the ECU to dump memory(reboot)..
I would contact your local dealership..verify the VIN and see if you fall under any recalls...such as reflashing your ECU...or like said before, cam position sensor or coil pack

drallafi
05-23-2005, 04:35 PM
I have an '04 M3 with about 21,000 miles. Every so often when cruising along at steady speed a very small skip can be felt, sort of like if one cylinder didn't fire for one cycle. It's very minor, most people don't even feel. But I do. Not big enough to really affect driveabilty or performance, and only happens once in a while.

Just wondering if any other owners have experienced this, and have any light to shed. I'm sure the dealer would laugh at me, it's that small, and I really don't want the tech driving the car around for an hour trying to feel it.

~bill


Yea, this happens to me too, but under heavy acceleration. It's happens pretty consistently, and only as the driver is it noticeable. For a while, I thought it was a minor slippage of the rear tires, but they have since been replaced and the issue still exists. Like you, I'd like to have it corrected, but there's no way the techs are gonna be able to diagnose the problem, so I live with it. Kinda stinks, though. I didn't pay $60k for this. Oh well.

Pinecone
05-23-2005, 05:27 PM
Have any of you taken it in to be looked at?

There may be codes in the ECU, or they may know of some things to check.

Mika
05-24-2005, 12:58 PM
mine does this too (infrequently) when cruising at highway speeds

GSIRM3
05-26-2005, 01:50 PM
I have an '04 M3 with about 21,000 miles. Every so often when cruising along at steady speed a very small skip can be felt, sort of like if one cylinder didn't fire for one cycle. It's very minor, most people don't even feel. But I do. Not big enough to really affect driveabilty or performance, and only happens once in a while.

Just wondering if any other owners have experienced this, and have any light to shed. I'm sure the dealer would laugh at me, it's that small, and I really don't want the tech driving the car around for an hour trying to feel it.

~bill

I have experienced the same problem you describe. I usually notice it under very light acceleration, or just cruising as you described. I have owned a 2003 M3 that I experienced the issue on, and also my current 2004 M3. I asked the dealer to check out the 2003 and they found no problems or engine fault codes. I thought about the coils, but my 03 production date was supposedly after that problem had been corrected. Now that I experience the same issue on my 2004, I am convinced it is not the coils but some quirk of the car, possibly an engine software glitch or something witht the electronic throttle. I have read posts on this and other boards from other owners with the same issue.

zshiek
06-02-2005, 10:03 AM
yeah i noticed this as well. Althought he normal driver in a m3 would never even pick up on this and relate it to a tire or suspension issue of rocks or road deteriation It is definetly a problem in the car..

I notice this problem most during 2900 - 3100 rpm's with below average acceleration.
I also notice this problem during full acceleration (sometimes) around the same rpms.. usually 500k higher..

I took it to the dealer and had the maf replaced out at 33k... That did help the harder accerlation problem a lot and car felt a lot smoother since now it knows how much air and fuel to mix together properly. I actually think this is a coding error in the ecu itself. The fuel map software might not be correct. If possibly try having your ecu flashed with the latest software.

My second guess is that this is a issue with the fly by wire junk that we use.. The sensor might be either too sensitive or not sensitive enough during acceleration resulting in the skip..

good luck and let me know if yoiu find out exactly what this is.. Again i've only had the car 3 weeks now and will be better understanding of issues hopefully by end of summer.

Pinecone
06-02-2005, 06:13 PM
Could also be a cam sensor going bad.

GSIRM3
06-03-2005, 05:19 PM
Could also be a cam sensor going bad.

Cam or Crank? I don't think either. Not familiar with a bad cam sensor. As I said in earlier post, I have experienced this issue on my 03 and 04 M3, so I can't believe I had a bad sensor, either cam or crank, on both cars.

Pinecone
06-05-2005, 12:31 AM
Well then live with the situation. But other people don't have this happening.

As for bad cam sensors, they are not uncommon.

BahnBaum
06-05-2005, 06:28 AM
Never happened to me.

Alex

GSIRM3
06-05-2005, 07:51 AM
Well then live with the situation. But other people don't have this happening.

As for bad cam sensors, they are not uncommon.

What purpose does the cam sensor serve?

Pinecone
06-05-2005, 08:27 AM
What purpose does the cam sensor serve?

To tell the ECU what the cam postion is so that hte VANOS can adjust them properly for the conditions. Rather important for smooth engine operation.

I have read of several having gone bad.

Gregmm
06-11-2005, 12:26 PM
I had the same problem. Turned out to be a bad VANOS. No problem since it was replaced.