Accerlerating problem

I have just taken ownership of a Honda Civic Lsi 1493cc 1993 model with 128,000miles & manual transmission.

I notice when I try to accelerate in 1st (and sometimes 2nd) that the engine is shaking despite having around 2500 revs or more, I have asked the previous owner and they have noticed this happening just before the car was handed over to me. What actually happens is the car shudders like it's about to stall, and I have tried using the accelerator more to give the engine higher revs (3000) and let the clutch out more slowly, but the car still shudders slightly whilst accelerating, it's almost like the engine is knocking but I haven't noticed the trademark knocking sound. Once the car is moving/rolling I don't experience this problem.
The car is quite old and has just passed it's emmisions test - it was right on the limit with Lamda=1.03. Could there be a problem with the engine/combustion? In truth I am not so experienced with the car.