Hi!
Here it is! I have a Weber 32 34 TLDE on my car.
The problem occours betwen 2700 and 3000rpm. It starts to struggle with getting up speed, but after 3k rpm it's ok again!
Same with petrol and LPG.
Only when I floor the pedal works ok. Maybe it gets some extra air on a gasket betwen the carb and intake manifold?
Makes me crazy!

Put a good fuelcleaner in the tank, and use a new fuelfilter.
Use Shell V-Power, which contains no ethanol like ordinary fuels, that will dissolve rubber gaskets etc.
How about the "winterstand" of the aircleaner, is it thermostatically or manual..??

Succes met het vinden van de oorzaak van dit probleem...!!

Thank you!

The "winterstand" fell of, and it was sucking cold air all the time! Fixed it! No more problems!
Thank you once more!

I tested the car and now the torque is much better, and the consumption got lower!
Thanks again for the tip!

The problem is solved.
It was the crankshaft sensor/ ignition trigger!

It's placed on the back side of the engine, pointing at the flywheel!!!

I didn't know that my Tempra has it....