1.9 jtdm Inlet manifold
After reading lots of info about changing the inlet manifold because of swirl valve problems on the net, mainly on vauxhall and saab sites I changed mine as the acctuator rod kept coming off.
What a huge differance its made, low down torque is much improved and now pulls like a train from almost tick over. The old manifold flaps were well worn with lots of play in the bushes.
It was a bit of a job to change with a fair bit of time sussing out what has to come off but the main things were.
The fuel pump has to come off and then one of the 3 studs for the manifold to clear.
The cam belt can be left in place because you can bolt the pump pulley to the mounting bracket with 2 bolts, I used 2 of the cam cover bolts, I marked the belt to both to cam and pump pulleys just in case it moved but it was fine.
I bought the lastest standard of Pierburg manifold, part number 55210201 from a vauxhall parts place, its the same part number as thoses sold for Alfa's but £60 cheaper