Trafic -04 vibrate during acceleration

Hi guys,



I have a trafic van -04 petrol (long version), which vibrates during acceleration. It have always done so but I've never figured out why. Google tells me that it's a common issues with these vans.



It vibrates during acceleration only, if I let go of the gas pedal it stops vibrating. I've had it at an renault dealer and they replaced somekind of gear thing (cant remeber the name, it was a couple of years ago), and also a couple of ball joints. But nothing removes the virations.



Anyone has any suggestions on where I should start the troubleshooting and replacement?



Thanks,

Hampus