sportrak 1.6i 1997


engine running slggish when cold.ive had anew head gasket fitted with new plugs, distributor, leads and water sensor since being in the garage. ther've adjusted the tappets as well, but it feels sluggish even through improved. now they are saying it could be the cat. which could have been damaged when the car overheated due to the head gasket going.could this be the problem(HELP SOMEONE),ive exhausted all possibilities. can anyone help.

Be sure to have checked: spra

Be sure to have checked: sprark plug gap, ignition timing, cylinder compression, air filter condition, fuel filter clogging.
It might be worth checking the O2 sensor values and injector flow rate and spray pattern. Unlikely to be the cat unless it's backed up with gunk. Can't think of anything else at the mo'