Hi guys would a faulty cat converter give poor engine performance and engine breathing problems on a 1.6 focus 2004 model ?

 

yes

 

as above!

 

Hi guys thanks for the replies, tried to have a look at cat but looks like the factory one piece one from front pipe to back box, car has done 85000 miles so possibly in need of replacement, also getting quite a bit of oil in the air box, do you thin the problems are linked?

 

Just done a compression test and results are

Cyl 1 = 157 psi
Cyl 2 = 156 psi
Cyl 3 = 155 psi
Cyl 4 = 155 psi

are these figures ok.what are they supposed to be please ?