I have a Cavalier 1.8i 93 with Multec single point injection.

I have a misfire which has suddenly got worse.I have had new plugs,leads dizzy cap & arm,air filter fuel filter,cleaned the EGR.
If you drive as normal it feels completly gutless,the slightest bit of load will have the poor little motor struggling,excesive fuel consumption,not checked the exhaust & cat yet,showing no fault codes,any clues?