Sta-Sta-Sta Stutter Under Hard Accel

Hi All,

This has happened twice now. The first time it happened I was in shift mode going from 1st gear at about 4k to 2nd gear. The car simply put fell on it's face big time when 2nd gear engaged so much so I thought i was going to be rear ended by a car coming up behind me.

The second time was cruising on the interstate in "D" I hit it to pass a car and it started to go then lost considerable power (not as severe as the first time though). I wasn't paying attention to what the tranny was doing and or if it dropped down a gear (I'm assuming it did).

The car currently has the Malone DSG tune and Malone Stage 2 tune with all emissions gear intact. Temperatures during both event's were in the 50's. In both occasions the car was fully warmed up and ready to go.

No CEL or check engine light flashing was observed but I'll scan again when I get back home this evening.

I've got three suspicions but no surety on any.

1. Exhaust Flapper? Thought it only occurred when cold?
2. EGT's got too hot ECU cut fuel and boost? Not aware of active regens during episodes. Possible in 50 degree weather? Not likely.
3. Transmission or transmission tune issues? Car putting out too much torque in cold weather? This one is at the bottom for a reason

Fuel filter has a 20k mile service interval, is it up to date? Sounds like it is starving for fuel from your description.

Thanks for the quick response the car has 46k on it. I did the fuel filter when i purchased it at 43k.

Minor update. Power Service Diesel Kleen is added every fill up.

Doubt that has anything to do with it but there it is.

Unless Brian says otherwise, I'd replace the fuel filter, suck the fuel out of the canister, and pre-fill it with Diesel Purge. That will give the HPFP and injectors a shot of cleaner and may solve the problem. Even though your fuel filter isn't old, a bad tank of fuel can cause all kinds of driveability problems.

I can look to get that done.

Should the fuel system be cycled/primed after the filter and Diesel Purge have been loaded up in the housing?

Diesel Purge or whatever that is will not help a slipping transmission.

Is this an official vote for DSG issues? Anything is possible but this seem more "cut-out" related to me i.e. boost or fuel.

There is also a randomness to it.

This does not at all sound like a DSG issue. And DSGs, by design, cannot "slip". The clutch(es) can, but if that were the case, you'd know.

You can try and monitor rail pressure, but the data rate may not be fast enough to see it on a scan tool. If it was enough that YOU can see it, then for sure the ECU would have seen it and you'd already have a low rail pressure DTC flagged.

So it would seem that many of the potential culprits would cause some form of DTC code since everything get's a sensor nowadays.

The question is what could be causing it that doesn't have a sensor.

Hmmm...

have you tried data logging to replicate the conditions? egr closes as you increase throttle, and rail does build quite fast too. Doubt it's anything EGR related, but I've seen some odd behavior from a malfunctioning ASV that shook the whole car.

Won't always throw codes for irregular engine behavior.

Thanks Owain.

Got home scanned motor and trans.

No codes as I suspected.

Haven't tried to reproduce it as thus far it's too random to try and reproduce.

I get on it plenty and it's only ocurred twice with differing severities.

Sent from my SM-G955U using Tapatalk

-:vw:- said:

I get on it plenty...

Sent from my SM-G955U using Tapatalk

Click to expand...

Case in point this morning, cruising at 60mph, put my foot in it until 80mph.

Pulled just fine. Boost peaked at about 24psi stayed in 6th gear the whole time though no downshift.

Hmmmmm no shift...

(shrug)

Occured again this morning. Pounced on it when the light turned green. In "D" 1st gear major hesitation, boost gauge fluctuating like crazy between 10psi and 15psi.

No CEL flashing or light up. Anyone have thoughts on what blocks to monitor in VCDS?

I'm going to pop open the fuel filter housing and have a look.

If this were my VRT I'd be checking and replacing plugs and spraying the coil pack with water to see if it was cracked.

All that is to say the behavior is very similar to a misfire issue...

My beetle has done the same thing a couple of times, just stumbled under acceleration while cruising around 50-60 mph. I was close to the fuel interval near 80,000 miles. Changed the filter, nothing since (I’m at 87,440). I usually fill my Passat at the same stations, no issues with it though. I run primarily Exxon mobil diesel.

Hi all, I've recently had this same issue first happen about a week ago and it has happened about once every other day. Always when engine temps are normal, flat road (coastal Virginia... not many hills), and when I'm in D, S, or manual shift mode. I've found that it is when I give it about 3/4 throttle and not WOT.

Just some background:
at 48K miles (not sure when last fuel filter was changed, bought the car at 43K)
No tunes, just a bare bone JSW, with emissions fix
sometimes when the stutter happens, gray-ish smoke comes out the exhaust
No CEL or stored codes

The most recent time I tried to force it by giving it some throttle, and when it happened I just held down the pedal. No significant change when I held it down but the stutter only lasted about 1.5 - 2 seconds and then the car took off like normal and didn't happen again.

I'm replacing the fuel filter tonight so I can try to post updates if and when something happens.

I filled up at a different station and it seems to have now gone away.

It was likely the fuel, I would think if it were the filter it would be much more consistent.

The filter doesn't just unclog or fix itself after a fill up.

-:vw:- said:

I filled up at a different station and it seems to have now gone away.

It was likely the fuel, I would think if it were the filter it would be much more consistent.

The filter doesn't just unclog or fix itself after a fill up.

Click to expand...

I'm glad it is working better for you! Mine hasn't had any hiccups since the filter change. Mine was pretty dirty but not as bad as some of my older TDI fuel filters have been... so who knows if its fuel related or filter related.

Good stuff.

My 2014 TDI Sportwagen has exhibited very similar symptoms the past 2 days. Sudden, but brief, power loss under acceleration. Usually accelerating from a standstill the car's power will drop of alarmingly, shudder twice, and then resume abruptly. It runs great, otherwise. It has done this maybe 4 times in two days? I've had the car less than 6 months. I am the second owner, bought it as a CPO with 37K on it and I just tripped 50K. It was serviced at the dealer about 2 months ago. Again, this problem just cropped up.