Please help.

My Mk2 2002 Punto has a juddering effect at less than 2000rpm. It has visited various Fiat dealers in the past 2½ years and whilst the problem has been cured at times temporarily it keeps coming back.

Once the engine is over 2000rpm it goes away,but it means that the car is impossible to drive at 30mph in 3rd or 4th gear.

At the end of my tether. So far have had

HT leads replaced 2x
Coil replaced but did not cure problem so Fiat specialist took it off and did not charge for part.
New plugs - cures problem for a while then comes back
New Lamda sensor - ripped off I reckon. Had passed MOT test day before!
Currently trying Redex - doubt that is the problem.
Cam belt changed (although this was not with the aim of curing problem)

Engine Management System light continuously on now. Juddering getting worse. AA man came out once when it would not start and checked plugs. Said it was firing weak on 2 cylinders he checked. Any suggestions? He though coil but that has been checked and discounted.

Wonder if ECU problem that has been mentioned in other threads has damaged coil and then HT leads. Would changing coil and leads remove problem?

Could it be any of the following?

Throttle Potentiometer
Residue on tappets
MAP sensor
Idle Control Valve.

Any help or suggestions would be greatly appreciated. The icon says it all!!:bang:

check your exhaust pipe mate, normally a nakerd exhaust causes juddering at low revs