I have a L reg Sportrak 1600ELXi It was running as if on 3 cylinders. I put in some fuel line and injector cleaner but it made no difference so I changed the plugs, rotor arm and distributor cap, two of the contacts inside the cap were broken. Since then it has been running rough mainly on tick over and some times cutting out but no trouble starting it again. I have found that the new plugs are very sooty they were fitted only a week before and when I stop after a run the engine smells very hot. It seems to me that it is running too rich. There doesn't seem to be any black smoke from the exhaust. I would appreaciate any suggestions on how the fuel can be adjusted or if you think it might be something else.