[sjf430]

I had this problem but it was coz of shit fuel, always filled 98, then for 2 days I filled somewhere random and the car would stumble just under 2000rpm and it was so sluggish, called my Indy mechanic he said run it dry and fill up 98, did it and runs like a boss, sometimes its the simple things, hopefully its something small for you as well, good luck man

[Taskmaster]

Originally Posted by DaanBMW

Ok, thanks ! everything sounds like what I am experiencing. You got it throw a CEL/code by just keeping at it ? Did you replace all packs or just 1 (?) that caused it ?

Yup. And replace them all.

[gudaev]

Got it solved today. Code showed a misfire in 3rd cylinder. Swap the coil with 2nd and the error followed it. Changed only one failed coil, though decided to change all spark plugs.

Btw, changed the gasket also.. http://www.e90post.com/forums/showpo...05&postcount=7

[jpregione]

what gasket is that?

[Kazeka6e]

Originally Posted by jpregione

what gasket is that?

i know this thread is super old but that's the shaft sensor gasket. part number 11-12-7-559-699

[ZeroSum]

Originally Posted by TheAxiom

It happens exactly like that -

You try to accelerate from a lower RPM in a higher gear (like 1500-2000) in 2nd or 3rd and the car will stumble and then accelerate fine. It would consistently happen at the same rpm in the same gear, and I though it was a issue with the stock ECU just having hiccups.

When I installed my OE revised tune, the issue continued if not got worse. Now it's at the point now that it will actually trigger a CEL and cause the car to stumble at all RPM for a full cycle. It's not noticeable on WOT upshifts from 1st -4th, only on partial throttle/WOT in higher gears and lower RPM.

Be prepared for a coilpack replacement.

same...and I have replaced all 6 coils and plugs.

[DaanBMW]

Originally Posted by ZeroSum

same...and I have replaced all 6 coils and plugs.

and... did that solve it ?

[ZeroSum]

Originally Posted by DaanBMW

and... did that solve it ?

Nope.

[DaanBMW]

Originally Posted by ZeroSum

Nope.

nice. I replaced vanos solenoids, vvt motor, both camshaft positioning sensors, spark plugs, maf. still not solved. the exhaust sensor made the biggest difference in my case.

wtf, are the electronics getting tired ??? I'm fairly sure now it's the stupid vvt system as it always gets worst when engine reaches operating temp, but what part of it I've not discovered yet.

[ZeroSum]

Originally Posted by DaanBMW

nice. I replaced vanos solenoids, vvt motor, both camshaft positioning sensors, spark plugs, maf. still not solved. the exhaust sensor made the biggest difference in my case.

wtf, are the electronics getting tired ??? I'm fairly sure now it's the stupid vvt system as it always gets worst when engine reaches operating temp, but what part of it I've not discovered yet.

Exhaust sensor?

[DaanBMW]

Originally Posted by ZeroSum

Exhaust sensor?

exhaust camshaft positioning sensor

[ZeroSum]

Originally Posted by DaanBMW

exhaust camshaft positioning sensor

Vanos?

[absolutepressur]

Originally Posted by DaanBMW

I don't feel my idle is in any not smooth (to clear the double negation: idle is smooth), yet I feel upon acceleration there is a hesitation esp. if engine speed is a bit low when I step on it, like the car gets bogged down then all the sudden it wakes up - oh, you want me to speed up - kinda thing.

I feel some people on here have slightly different issues but due to the wording think it's all the same issue. Based on your description I'd say you and I have the exact same issue, and that ours is different from the OP's. His hesitates for a few seconds, whereas our issue is more on the order of a fraction of a second. Mine is anyway. As you say, it's like I caught the car sleeping, startled the shit out of it, then it runs like a bat out of hell with no issues.

To be more concise, it doesn't feel like some of my cylinders are misfiring, it's like all power is cut for a fraction of a second as I give the throttle a little punch from cruising load ~1800 rpm, then the power comes in like a hammer and sends a pretty big shock into the driveline (6MT).

It's also a little random when it happens, it's not totally reproducible, and never after I've started to drive the car spirited.

Based on that I'll believe for me it's the VANOS solenoids and/or MAF as was suggested by someone early on. I'll take a look at those first. I have a super hard time believing it's a coil issue since it runs great at full load, when the in-cylinder density is the highest and therefore the hardest condition to jump the plug gap.

I also have INPA so I might take a peek in there, but I have no SES so far. Chime in if you have any advice in the mean time.

Come to think of it, I might be a little more scientific about this and only change one thing at a time The MAF sounds like the lowest hanging fruit.

[ZeroSum]

I had a similar issue and ended up just buying both vanos and I was good to go.

[tom.gnade]

I'm having what I would describe as the same issue, seems like the throttle response is absolute crap anywhere below 3k rpm, and there is a solid 1 second lag when you push the pedal. It's already a heavy car and the throttle response at low speed/low RPM is terrible, even with an AA tune, which makes it feel like a pig. My wife's Sienna weighs thousands of pounds more but when you push the pedal, the RPM response is immediate and proportionate, which makes the car feel like it's very responsive, because the output matches the input. It's very frustrating to me. My car only has 30k miles, so I don't see how I should need to replace any components at this point.

[Snoball M3]

Originally Posted by tom.gnade

I'm having what I would describe as the same issue, seems like the throttle response is absolute crap anywhere below 3k rpm, and there is a solid 1 second lag when you push the pedal. It's already a heavy car and the throttle response at low speed/low RPM is terrible, even with an AA tune, which makes it feel like a pig. My wife's Sienna weighs thousands of pounds more but when you push the pedal, the RPM response is immediate and proportionate, which makes the car feel like it's very responsive, because the output matches the input. It's very frustrating to me. My car only has 30k miles, so I don't see how I should need to replace any components at this point.

I'm having the same issue, but everyone says its the coilpacks, but I've been told to invest in a OBD 2 BMW Spec before buying parts that way you know what it is for sure, I haven't replaced but have ordered them , I'll let you know the outcome hopefully it solves the problem....

[tom.gnade]

Originally Posted by RSKY65

I'm having the same issue, but everyone says its the coilpacks, but I've been told to invest in a OBD 2 BMW Spec before buying parts that way you know what it is for sure, I haven't replaced but have ordered them , I'll let you know the outcome hopefully it solves the problem....

Would love to know the outcome. I'm having thoughts of a 335is or an M3 to hell with the payments at this point.

[Snoball M3]

Originally Posted by tom.gnade

Would love to know the outcome. I'm having thoughts of a 335is or an M3 to hell with the payments at this point.

Hahaha thats the same attitude I have I'm in between those 2 also but more towards that M3, I'd rather dump money on that thing

[DaanBMW]

Originally Posted by tom.gnade

I'm having what I would describe as the same issue [snip]. My car only has 30k miles.

Wow, that is a bit low. I'm at 115k miles.

Originally Posted by RSKY65

I'm having the same issue, but everyone says its the coilpacks

The only reason I did not do coils is that that should make it worse at high loads / high rpms, whereas mine is mostly at low speeds / near idle.

[tom.gnade]

I've figured out part of it; throttle bogs pretty bad at low RPMs in a high gear. Since D mode likes to run up the gears quickly to keep RPMs below 2k when cruising, if you punch it the transmission wants to downshift first, and you have to gun it hard to convince it to do that, so it seems to lag for quite a bit of time then surges quickly to 3 or 4K after the downshift. The solution is DS mode, which keeps the car in a lower gear and higher RPM by default, and is ready for a throttle input, or to use the paddle shifters to force the downshift quickly when you are cruising in D and want to suddenly accelerate. My guess is this effect is much less noticeable in a DCT because of the shift speed.

[Snoball M3]

I replaced the coils ended buying three bad ones and throwing 7 codes, so put back 3 old ones and everything runs normal now but still having that hesitation n wants to stall on light acceleration.... I

[tdavis42]

Originally Posted by RSKY65

I replaced the coils ended buying three bad ones and throwing 7 codes, so put back 3 old ones and everything runs normal now but still having that hesitation n wants to stall on light acceleration.... I

Could be the fuel regulator or fuel pump.