Loss Of Power

[Guest malc]

Hi, I have a 2000 2 ltr Zetec Mondeo and it has developed a loss of power, I have had a good look and have found that there is a T off of the exhaust manifold which has 2 pipes which appear to go to a grey box, these pipes have blown off of the manifold, I replaced them and the car runs fine for a while but then they blow off again pipe clip did not do the trick would it be the cat yes this is the same car Dave-G is that your Dog or is it Paris's

 

Any ideas

 

 

thanks ;)