[fredcase]

2007 e90 335xi MT, FBO

Started happening after I did multiple jobs on the car, so it will be hard to pinpoint, But, could use all the input possible before I start throwing money at it.

Only does it at light throttle, after the car has warmed up. 1st-3rd gear, while trying to maintain a speed. Acceleration or deceleration is fine. Will do it with cruise control on. Feels like i'm tapping the gas pedal. No codes. Pulls great. Did all the MHD resets available and with JB4

Multiple jobs were,

Valve cover gasket, OFHG, Valve clean, newplugs, JB4 install with bef. Did those then got vanos codes. (likley from spilling coolant all over them and the car sat for 3 weeks while I picked at the above jobs)
Replaced both vanos.

I did re-use the intake manifold gaskets and throttle body gasket. I will replace those soon if I cant sort it out first. (have parts now)

I plan to try the following in this order, starting with the cheapest,

1)Remove jb4, try flash only. (hope thats not it, love JB4, but I bought 2nd hand)
2)Intake manifold, throttle body gaskets, and vaccum hoses
3)Maf and Map sesors
4)pre cat o2 sensors
5)post cat o2 sensors

https://datazap.me/u/fredcase/log-15...log=0&data=1-4

https://datazap.me/u/fredcase/log-15...log=0&data=1-4

The only does it after warming up is throwing me off.

[OlliD]

Same here - curious about the solution.

[fredcase]

Originally Posted by OlliD

Same here - curious about the solution.

I'm hearing its the sign of an injector going out. I'm trying to find an affordable scan tool to test running smoothness

[dpaul]

Originally Posted by fredcase

I'm hearing its the sign of an injector going out. I'm trying to find an affordable scan tool to test running smoothness

INPA has that function. Engine->MSD80->Live Data (F5)-> Rough Running (F7)

[Spyro235]

I've had the low throttle surge issues Precat o2 sensors ended up being the issue. My adaptations still go haywire after a few months and I need to reset adaptations, because I didn't realize my o2 was bad. I just got codes recently, and I had been getting surging issues for a year and a half. My o2 was even reading AFR's at the time.
basically, the dying o2 had been causing my lambda adaptations to go crazy.

When I fixed the surging, I did a few things at the same time so I can't be positive which really solved it. I cleaned my vanos solenoids, and switched them. I reset my vanos adaptations and my lambda adaptations, and then my surging went away.

Mine was only after it was warm, car operated perfectly until it warmed up. I had a stutter on initial tip in, and my car stalled out a few times coming to a stop when I pushed in the clutch. If I held the accelerator in neutral at 1kish rpm, it would bounce between 1100 and then stumble down to 500ish, and oscillate like that. At 3k rpm, at steady state 82mph, I would get a crazy surging and bucking. Feel free to ask me any questions. I was about 3k in repairs into trying to fix this, as I found I had a cracked valve cover, (700+ install, at the time oem was the only option), and then all injectors and coils, and a few other things I can't remember off the top of my head.

[fredcase]

It's not the jb4.

I'm gonna try to clean/test injectors.

Then will try o2 sensors

[fredcase]

Put in new intake manifold gaskets and throttle body gasket. It's actually worse now, and the smooth control on carley shows cyl 3 instead of 5 staying high. Wtf?

[Spyro235]

Did you replace the O2's yet? Replace the precats, and then reset the lambda adaptations. I'd find it crazy that you bothered to do the intake manifold gasket, and the throttle body gasket, without smoke testing the bay.
If it still surges after the O2 sensors and adaptation reset, then go to a good shop with a smoke machine, and have them pop a DV off, and pump smoke into the intake tract. Don't throw parts at this issue like I did!

[fredcase]

Originally Posted by Spyro235

Did you replace the O2's yet? Replace the precats, and then reset the lambda adaptations. I'd find it crazy that you bothered to do the intake manifold gasket, and the throttle body gasket, without smoke testing the bay.
If it still surges after the O2 sensors and adaptation reset, then go to a good shop with a smoke machine, and have them pop a DV off, and pump smoke into the intake tract. Don't throw parts at this issue like I did!

o2's are expensive af. And a pita to install on an xi, gonna do these last resort.

Still under the assumption that it was something I did wrong when doing that work.

Intake manifold and throttle body gaskets took me an hour, and was $100 cad

[fredcase]

HELP!

oil pan gasket almost done, forgot to mark pre cat o2 sensors. So, connection at top of motor, one front, one rear, what one is bank 1, or bank 2? front turbo, or rear turbo?

[CeeWhizzle]

I had an issue like this. However it ended up being a connector from one of the coil packs that was somehow backed out and wasn't fully seated.

[raptorman5174]

for an old thread but still a relevant issue

So what the consensus on this?

Precat 02's?

or

Bad Injector?

[Shahncho]

Following. I'm having the same issue

[valibad]

Had this and fixed with all 4 o2 sensor.