Welcome to the forum,Ogre Battle.
Sounds as though the first Lambda sensor is faulty.For the readings to be that far out,it has to be something telling the
to over fuel,and this is usually a consequence of the Lambda sensor telling porky pies....
There are two sensors in the system,one before the cat(which senses the oxygen in the exhaust gases and tells the
to alter the fuelling accordingly) and one after the cat(which checks that the cat is working).I suspect you have problems with the first one before the cat.
If you do a search for Lambda Sensor or Oxygen Sensor,you should get the information you need.
Good luck,and let us know how you get on.
(I'm sure a mod will move your post to a more appropriate section).