miss fires

[clanger_1967]

hello people my name is gi my fronty is porly it suffers missfires this only started since it went into garage for gearbox fitting sofar to date the garage has replaced plugs, fuel filter,air filter, gearbox oil filter, lamber sensoryet no joy and to make things worse it now has gearbox oil over heating if any ideas please help i love my fonty and just want to make it better

[stretch]

Hi would help if you filled out your profile or posted in the relevant section so we know which variant you have.