Violently jumping

[Neilburb]

I have the 2l tdi mk6 2009 golf my car has had a stage 3 remap about 3 years ago. In the past year my car has developed a strange problem if I fully accelerate down hill the car violently jumps but keeps going also if in 4th and 5th gear in low revs if you put more than half the accelerater down the car juders quite bad in low revs. There are no faults showing at all and I have even had a diagnostic plugged in while driving and shows no faults I have had a new egr valve and new fly wheel and clutch kit fitted has anyone else had or herd of this problem.

[Crasher]

Sounds like fuel starvation. The early Golf 6 CBAB engine had a complex triple pump delivery system and the in tank pump can fail causing the engine bay mounted electric pressure pump to struggle and cavitate which doesn’t always leave a fault code or even show up as a pressure fault. It does however usually cause the electric pressure pump to make strange buzzing noises.

[Neilburb]

That's brilliant thank you now you mention it the pump does make a noise it also makes a tapping sound when the engine is turned off do you know if these are upgradable or is it something il just have to live with.

[Crasher]

I have had quite a few do it. Usually a new in tank pump is the only thing required. The original unit has been superseded by a new number 1K0 919 050 AB and you can get a cheap one from Euro Car parts PWM Fuel Pump or buy a genuine one from VW for £211.90 I don't know who PWM are and if I had the time I would get one from Bosch, Pierburg or VDO. Make sure the connections are not put back on the wrong way around, it is very easy and looks correct, I had one send me around in circles until I worked out what the other garage had done wrong.

[Neilburb]

Thank you very much you have been a massive help this is something that has been driving me mad for a while now.