Hello and welcome, have you done a compression test
no not yet can you give me some idea of possible proplems i forgot to sat the two cylinders are beside each other thank you
This could be a head gasket fault.
Compression testers do not cost much, you take all of the sparking plugs out, and just crank the engine on the stater motor,noting the readings, if the two that you think that are not firing are low then that is the problem.
Halfords and other shops sell them