1998 2L Sharan Sensors

[pinarello]

Can anyone help!

My 1998 2L Sharan continually hesitate/run lumpy between 20 & 40mph. The car has had this problem ever since I bought it 2 years ago. When I bought it I thought it would eventually go as I serviced it and changed plugs, leads filters etc. but it hasn't.
Having changed all the following component:-

Distributor cap
Leads
Rotor arm
New distributor
Crankshaft sensor
Coil (twice)
Cleaned throttle body

I have now removed each of the following sensors one by one to see if anything changes!!

Lambda Sensor
MAF meter
Air box temp sensor

All these sensors are now disconnected and it has made absolutely no diference to the running of the car. It does exactly the same as it always does. It runs ok when the engine is cold and on choke but when it starts to warm up it gets lumpy/hesitant!!

At 50mph upwards it seems to run fine.

Surely disconnecting the above sensors would make a difference to the running of the engine?

Any advice!

Thanks in advance