I could do with some help sorting a misfire !!

Engine;

2ltr zetec black top with pr 45 dcoe carbs,engine has done only 1500 miles approx. and carbs are a few months old,so all in good condition.Contolled by omex 200.

Symptoms;

Tickover is fine and stable/smooth,rev the engine also smooth.However anything over around 2500rpm on a steady throttle ie cruising at 50 60 plus mph and the engine feels hesitant/slight misfire/and a bit rough.If you boot it it's fine until you throttle back and cruise.

It is also drinking much more fuel !!

No 1 plug looks a bit black and no2 very slight,no3 and 4 look brownish !!

any thoughts on what could be causing this would be greatly appreciated.I don't have RR facility anywhere around me.

anybody had any thing similar??

cheers.

Are the carbs balanced and set up correctly.

yes I think,however will check they are balanced again tomorrow.This just suddenly started a couple of weeks ago out of the blue !!Wondered if it could be a lead or plug,or possibly bit of crap in the front carb.

Just looking for things too try before pulling the carbs to bits..

Could also be coil pack. I would just change the lot.

Thanks guys,I will have a play with her today.