thanks for your thoughts.i have the print out and have checked it to the details i posted earier and they are as printout.the guy who done the mot thinks the problem could be the age off the exhaust ,and have lots of very small pin holes(the exhaust has been repaired in the past,dose not appear to be ready to fall off) the mot tester found it strange that the lambda was approx 1.3 at engine speeds from app2-4000 rpm,closing comment from mot tester was poss air leak on inlet side but had not seen this on the 4 pot eng.