[Luckystrike24]

09 335Xi 85k miles, manual, 100% stock since car was new.

Problem: 3rd gear, 60 mph, floor it to 80, pulls hard, then falls flat / surges etc, pulls hard, falls flat, wash rinse repeat. 4th gear it does it in the 60-80 band but 80% less noticable. 5 / 6 gear no issue. 1 / 2 gear no issues either. Feels like weather dependant, only came about when the weather got a lot warmer, wife thought was issue with snow tires not gripping. I have summer tires now, but drove before install and could tell it wasn't tire related.

Idle solid, no long cranks, no shakes, studders, etc. Very clean idle. No other drivability issues except under high load as outlined above.

No codes, no shadow codes, nothing even with extended intentional driving while surging.

New parts (less than 3 months): valve cover, flapper valve, pcv valve, injectors (index 12), spark plugs (bosch), coils (delphi), low pressure fuel sensor, air filter, all vacuum lines new, valve cleaning. Hpfp replaced 30k miles ago.

Tried: new gas, reset all adaptations with INPA.

I'm on original stock turbos, have rattle, BMW excluded my vin for unknown reasons, original boost solenoids, original diverter valves, charge pipe, original vanos solenoids, original clutch flywheel etc

I can't log because I don't have mhd or bt, but I have INPA, which is a complete bummer in trying to provide more useful information to the community, but looking for any advice or input. A lot of threads that are similar don't have the amount of work I've done, and stop at valve cleaning, injectors, plugs or coils. Since I've done all that and more, looking for input above and beyond the normal that may have fixed someone else's issue that may have gone down this road already.

[BQTuning]

[Luckystrike24]

What options are available for logging on stock / unflashed ecu? Can I log with a bt cable w/o flashing ecu?

[Velocity26]

Borrow my Cobb ...

[Luckystrike24]

Do I have to flash the ecu before I can log with a Cobb or bt? I don't have a battery charger for the initial flash and wanted to stay away from that for now. Otherwise I'd have the mhd on hand already.

[Luckystrike24]

Took it for a spin this morning it's 44 out and maybe seems less noticeable compared to yesterday in the 60's but it's still there and turning off dsc / traction control had no effect.

I disengaged the awd system by pulling fuses the car ran thru the rpms wonderfully, no hesitation, jerking etc.

[Velocity26]

Not sure if it has to be flashed, thought it just had to be un-married from my car so that it would be available to flash. FWIW, mine is IJEOS.

Kinda looks like you have excluded the engine somewhat, but it would be available to you if you should need it.

Leo

[Luckystrike24]

Yeah, thinking it's transfer case related. Going to flush the tcase and front diff and see if it changes at all, it's due anyway.

[theweebabySeamus]

Originally Posted by Luckystrike24

Yeah, thinking it's transfer case related. Going to flush the tcase and front diff and see if it changes at all, it's due anyway.

What're the tire sizes you're running currently?

[Luckystrike24]

I had a winter setup 17 225 45 square (Nokians) running staggered now 18 225 40 and 18 255 35 (pp s04) but it's an oem staggered setup that came on xi's. The surging was with both sets of tires.

[theweebabySeamus]

Originally Posted by Luckystrike24

I had a winter setup 17 225 45 square (Nokians) running staggered now 18 225 40 and 18 255 35 (pp s04) but it's an oem staggered setup that came on xi's. The surging was with both sets of tires.

I know they have a really small tolerance for differing tire sizes, but that's obviously not it. Must be some sensor in the AWD setup.

[SM335i]

I had the same thing on my xDrive with 92k miles. I have a 2010 with automatic transmission. It kept happening, then like a month later my waterpump died. I changed it along with the thermostat and it's been 2 weeks, no more hesitation/surging.

[jskin1510]

Don't mean to bump an old thread but not too much info in here so far. I searched and found this, and sounds pretty much exactly what's going on with my car as far as the symptoms.

106k miles on it. 2nd gear pulls hard and as normal but for some reason 3rd and I believe 4th gear both hes this slight off/on hesitation if I'm stepping on it. No CEL lights or codes pending or confirmed. I had already replaced plugs before I got my JB4 and 3 coils packs since. Just the other day, replaced the other 3 coils. I was thinking it was maybe a misfire that hadn't been "bad enough" to trigger a code yet.

Not sure what it could be. I guess the last post makes sense maybe water pump is getting ready to go?