A few blips, slight stumble that goes away in sport mode.

L

LabRat

Member
2004 2.5
1st to 2nd in auto, 3 blips and a drop from 1900 rpms to approx 1700. Sounds and feels like she’s going to fall on her face, then recovers.
2nd to 3rd, 2 blips, drop of 200.
3rd to 4th smooth, runs perfectly
4th to 5th smooth, perfect.
Hit the accelerator, upshift smooth, runs like it is suppose to. Get the revs up to 4000 and nothing noticeable. Runs like a car should.
No codes thrown!

In sports mode, no noticeable problem, wind out the gears and she just wants to go.

History: I purchased it a few months ago (stole it) and it was obviously poorly maintained.
Ran like crap but was enthusiastic about learning about it. So far, my work has been
DISA rebuilt, ICV removed and cleaned, Siemens injectors removed benched cleaned ,0% variance @2500, 0% variance @6000. new plugs. Still no codes, still stumbling.
My thinking, as mentioned in a previous threads was electric, fuel, vacuum.
With no codes and with the stumble disappearing in SM, but immediately comes back in auto, I had this strange thought. Is there a vacuum setup that gets bypassed in SM because I’m leaning towards vacuum.
Keep in mind I’m an old muscle car guy and use to set a dual point distributor with a match book cover when they closed up on a back road, but willing to learn all I can.
 
I have a manual but it sounds like the same symptoms I had. It used to feel like there was a massive flats pot in the Rev range at around the same rpm's as you've said.

It turned out to be a dirty maf sensor, caused by an aftermarket induction kit. It must have cleaned itself up when I refitted the standard air box, as I haven't had any problems since.

I believe the maf sensor is a thin wire and this can get gunked up with oil, dirt or debris.
 
ben g said:
I have a manual but it sounds like the same symptoms I had. It used to feel like there was a massive flats pot in the Rev range at around the same rpm's as you've said.

It turned out to be a dirty maf sensor, caused by an aftermarket induction kit. It must have cleaned itself up when I refitted the standard air box, as I haven't had any problems since.

I believe the maf sensor is a thin wire and this can get gunked up with oil, dirt or debris.
Click to expand...

I think Ben's made a good point here. OP Try taking it out and cleaning with a MAF cleaning spray (note dont use standard carb cleaner) and see if it has any effect
 
I used the MAF spray, went for a quick run and no change. It was pretty clean to start but sprayed the crap out of it anywayIMG_0547.JPGIMG_0546.JPG

I'll take any and all ideas. Thanks in advance.
 
Went for a ride tonight, got into it a little, and started to misfire, badly, real bad, check engine light on. Limped to a friends house slowly. Turned it off. Fired it back up and it ran like nothing was wrong. Scanned it and 2745 DTE misfire on 6. A few months ago, there was a misfire on 5. Swapped it with 1 and nothing happened. This time swapped 6 with 5 and nothing. Carb cleaner sprayed every vac line I could see and no change. I just don't want to throw parts at it. A set of coils? ECU replacement?
https://circuitboardmedics.com/2000-2006-bmw-siemens-ms43-dme-ecu-misfire-repair-service/
Not sure what direction to go next.
 
SOLVED! Replaced the coils. Wish it was indicated when I swapped them out because just parts replacement ain't my style.
Otherwise, I had a blast driving around. I'm hooked.
 
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