K jet running weak?

1st trip out in my 1800 GTI this weekend, pretty much without a hitch except under light acceleration the car seems to splutter slightly like its mixture is weak. Seems to cruise OK. I think its weak under full throttle acceleration also but not so noticable other than it feels down a bit on power compared to other 1800's I've driven. I've tried adjusting the CO screw but that makes no difference other than it picked up the idle revs a bit. I can't hear any air leaks and I have changed the inlet manifold gasket.

Any ideas?


Thanks
Graham

The only way to tell is to measure it, since weak running, rich running and ingition problems all 'feel' exactly the same from the driver's seat.

Think I've sorted it. Advanced the ignition by 2 degrees! Made a huge difference!