Technical Punto MK1 55S hesitation & uneven running

[KeithT]

My old 1994 55S is still hesitating under light acceleration & partial load. I have just had it tested very carefully & no conclusion!
No faults on ECU, lambda OK fuel pressure 1.5 bar steady at all loads.
Vacuum gauge on air cleaner vac pipe shows vacuum varies as revs vary (drop) at fixed throttle position 2000 down to 1600 it does this at random times. Engine starts fine tickover fine, hesitation - holding back at part throttle runs fine at full throttle.
We did find the pipe from MAP sensor was split, renewed it engine seemed to run properly but when test driven reverted to hesitation at part throttle(ba**ard)
Lambda sensor is recent, CAT replaced a year ago.with new exhaust.
It struggled to pass MOT disturbing the Lambdas sensor plugs seemed to affect the emissions & it passed.(6 months ago)
Do you think relacing the MAP sensor is worth a try?
I took it to a Fiat dealer last year with the same lack of any obvious fault. this problem has been with me a long time & I've sort of lived with it but it is still a PITA.
Any injection wizards got any ideas?

 

[sab5791]

Hi There. It could be that you have a faulty coil pack. But before this check your plugs and leads. A broken lead can show these signs. Failing that it could be the sensor or a head gasket fail.

 

[KeithT]

Hi There. It could be that you have a faulty coil pack. But before this check your plugs and leads. A broken lead can show these signs. Failing that it could be the sensor or a head gasket fail.

I have got a spare coil pack so could change it leads etc are fairly new compressions are good no coolant loss oil consumption is minimal, mostly leaks! cam box & belt end of engine. I don't really want to spend £100 on a sensor that may not be faulty, maybe a tested 2nd hand one if I can get one.

 

[Uno driver]

I would replace whole throttle body with used one if you are able to get it cheap