[BigTone]

Have a 14 plate i30. When I pull away or am plodding along at about 1250 rpm in 2nd or 3rd gear and put my foot down the car will kangaroo until about 2000 rpm when it will take off and drive properly. Had the fuel filter changed which made no difference. However if I unplug the air flow meter (maf sensor) the car runs smooth as silk apart from running in limp mode. Had the maf swapped but it was for a used one to see if it made any difference which it did but still didn’t feel quite right. Am now having to run the car with the maf unplugged but in garage mode. Do you think a new maf sensor would cure this as they are quite Expensive for a genuine one and the garage that we use (car is a taxi) aren’t very good at diagnosing things.

Many thanks
Tony

[Bogdan1986]

Hello, Tony.
I changed the MAFS in my diesel i30 a few months ago because of a rough idle and intermitent limp mode. It would "kangaroo" at times, but only when the engine was cold. I used an aftermarket unit and, at first, it did make a difference for a few kilometers, until the ECU learned the new part and the engine started acting the same. I did get an EGR position error too, though.
After changing a few more parts in the EGR system, the symptoms are still there.
A new idea a mechanic friend gave me is that the DPF might be melted inside, thus restricting the exhaust. Sometimes it doesn't throw a code, but it does decrease turbo compression and forces more exhaust gasses through the EGR system. It chokes the diesel engine, basically. I need to make time to disassemble the DPF and visually inspect it, in order to confirm this theory.
However, it is a very low chance this is what is happening to your car.
Might be the MAFS, might be the turbo pressure sensor (TPS)... Are you sure the car doesn't throw a check engine light, at all?