running rough

i recently changed the head gasket on mine and it was running sweet for a few days but has now started running rough. the plugs are coked up so assume it  must be a mixture problem. i've checked air filter but it's a new one and still clean, have checked all the breather hoses on top and they are fine, also checked compression on all cyclinders and they're fine, tried emptying and refilling the coolant making sure of ratios, even changed the plugs… no improvement… am not too keen to  start messing with the air flow meter as i don't want to make it worse..are they easy to adjust/work on?….any one got suggestions?

They are quite easy to adjust, though I would make sure everything else is spot on first. Lots of people who don't necessarily know what they are doing over adjust the mixture to compensate for other problems.

You really need access to an exhaust gas analyser too, otherwise you don't know how much out the mixture is to start with.

am hoping to buy an exhaust gas analyser this week, will check it first and then maybe tackle the mixture adjustment.
cheers

have bought a gas analyser off ebay but got impatient waiting for it to arrive so tackled the mixture screw without it. there was a thread on the fuel part of the forum where someone described how to adjust the mixture by ear. have tried turning the mixture screw both directions and the idle does go up and down but cannot find the spot where it will run evenly. the rpms just peak and trough, going up to about 1000 rpm and then dropping to nearly 500 rpm. i can drive the car but it runs like a pig unless i really put my foot down. i'm thinking it might be the valve clearances, before i get the rocker cover off, any one else with any ideas?

also thought i'd mention that i've also recently renewed the injectors seals…would this have an affect??