Probably a loose throttle cable, very easy fix, just take a look at it.
How tight should the throttle cable be?
By the way, this is what I've done so far:
-Checked timing
-Changed the sparkplugs, wires and distributor cap.
-Changed both the intake and exaust gasket (the was a small leak in the intake gasket).
-Changed the entire mono-jetronic injector unit.
-Checked for vacum leak, but couldn't find any.
-Checked all the ground cables, all seem fine.
-Changed the lambda sensor.
-Changed the blue temp sensor.
-Changed the battery.
I know that the catalytic converter has been gutted, but this shouldn't cause any problems, aside from giving the exaust less restriction.
Is changing the engine mounts a difficult job?
The engine seems fine aside from the throttle-lift off jerking. It really accelerates both quickly and smooth, but it's a pain to drive in the city with all the start,stop and slow driving

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It recently passed the EU test (m.o.t) so I'm planning on keeping it for at least two more years.
All other tips on things to check out is appreciated

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