My 2015 2.0 tdi has developed an odd, intermittent jerk, like a sudden cough. It tends to happen after the oil temp has reached 60 or so, but not necessarily when accelerating, and sometimes when idling in neutral. Sometimes it will happen two or three times in relatively quick succession, then it may not do it again for 20 or 30 minutes. I've also had a couple of stalls when pulling away from standstill after the car is warmed up. There are no warning lights, and both garages that have had a look have found no diagnostic codes. It's had new fuel and air filters, but the problem persists. However, I bought myself an ODB II reader in the hope I could capture something when the issue arises. This scanner also shows no error codes, but does show a TP(%) of 89. Could this be a throttle sensor failure, maybe affecting the ECU and causing the jerking? I'm not enjoying driving the car, as I'm on edge waiting for the jerk, and I'm a bit paranoid about going on a long journey in case the car lets me down badly. Any ideas will be gratefully received!

Throttle position sensors do fail; but firstly - I would get yourself some decent kit for your car. Please go invest in a VAG ODBEleven dongle. Car may throw codes that aren't picked up by a standard reader.

My pick of these kinds of fault would be: Throttle Position Sensor and valve (check that it is actually closing - it is possible that it is filled up with crud) as well as a stuck open EGR valve (again, because it is filled up with crud).

My first port of call would also be - check your oil level (make sure that is good) and get some Super Diesel (pref Shell V-Power) into the car and take it on an Italian tune up. VAG engines do not like to be tickled....they need good long fast runs to keep them working well - keep in 5th gear if manual and manual mode in 5th gear on a DSG). Throttle position valve - this will probably need cleaning by hand (alcohol wipe), the sensor may also need cleaning (use an alcohol wipe, but the EGR valve should respond well to some super diesel.

Many thanks for taking the time to reply. I'm not particularly mechanically adept, and I don't have the correct tools, so I can't do this myself. But it's good advice I can take to my garage and ask them to have a look.

Thanks again.

I'm having what appears to be the same issue, intermittent and logs no fault codes (I'm using VCDS).

Wondered if you resolved your issue @Billyb52 ?

I've removed the air intake pipe and see the throttle flap is clean, at least no soot present..

Wonder if the throttle body is sticking at some point and not closing properly randomly.

Alasdair

After 2 local garages used their diagnostics and found nothing, I finally took the plunge and paid for a VW/Skoda specialist investigation. They found a problem with the engine speed sensor. This was replaced, but they said that if this didn't cure the issue, it would be a gearbox fault. However, some weeks have passed and I've done about 1000 miles since the sensor was replaced, and all is good so far. Diagnostics, plus replacement, plus labour and retest came to £550. Not cheap, but I'm happy that my car seems fine now......touch wood!

Thanks for the replies, appreciate it.

I wondered about the throttle body too, weird that nothing is logged?

Think I'll spend some time in VCDS and see if I can log/capture throttle body/speed sensor when the issue occurs..

I've also changed the fuel filter.

I hesitate to muddy the waters with this but the only other thing I can think has changed since the problem is use of Esso diesel instead of Shell...

Maybe a full tank of supreme diesel would help clean things up although at todays prices would double the value of my old 1.9tdi. Hope a good going over with VCDS will pinpoint something. It may be the throttle position sensor that is out so perhaps a throttle body alignment with vcds is required.

Alasdair