I have had an intermitent CEL which has been coded - the code says second lambda sensor CAT or wiring between. I have a 53 reg estate 80K. Other then this the car has been fine. THe cel often goes on a day after refuel, and eventually goes off after a week or so. THe fuel cap seems OK. Its going on and off more often has been off Ive seen say 4 CEL in last 3-4 months, my mechanic is loathe to fix an intermitent fault Besides reading the code is there other diagnostic kit which willl help. My mechanic is concerned about taking the car apart to check wiring when it may be a red herrring. Perhaps this is a common fault. ONe solution would be to replce the LAMDA cheap but may not work.

Im Loughborough based.
Thanks

 

Should say the problem started when I filled about 1/2 the tank with 97 ron fuel rather then 95.