Might have sorted it
 

I turned the mixture richer today (havn't checked the vacuum pipes yet) and it got a bit better.... If I mess with this again how di I know I'm within acceptable limits..... are those 'Gunson' type home DIY emmissions testers any good and if so what reading do I need to look for?

i don't know what your original post included, but the MFI part load and idle CO% are shown in the "check, measure, adjust" document which can be found in the Technical Document section of the PP website. you have to find your year /engine type, and look for their respective settings.

i bought a GG tester because if felt that without it, i was cranking the adjustment screws and looking for black smoke. that may work for some, but i was looking for a little more than that.

the GG tester is not a substitute for a $ exhaust gas analyzer used by professional shops, but it gave me the extra precision i was looking for. also, i didn't find it too practical to attempt to do a part load CO% measurement. i sure as heck tried, but i'm not convinced i accomplished much.

so, to summarize, i used the GG tester to set my idle mixture, and relied on the absence of hesitation and later, plug burn characteristics, to adjust/confirm part load settings.

and i would have attempted neither without being thoroughly familiar with "check, measure and adjust". heck, i sure hope that was your original problem.....................