Thanks, they told me today the fuel pump may be faulty and this could be causing the management light to come on. the diagnostic did show oxygen sensor on the report. This is the 3rd garage. the first said lambda, the Kia dealer said spark leads, bought new ones from them but that didn't work and they were stumped after that, wanted me to pay 4 hours labour to 'investigate'.
This problem still not resolved, 3 garages can't find the problem. One suggested replacing the engine. The car runs fine if a little spluttery at times. Is there a way to turn off the engine warning light permanently?
I had a problem with my 03 Rio and the oxygen sensor, but it was my fault! The wiring loom for the sensor is very close to the radiator fan and poorly tied down. When I changed the plugs I accidentally knocked the loom. I didn't notice and a few miles down the road the engine management light came on. Went to the garage as I'd only just just bought the car, and they put it on the diagnostics machine but couldn't get any sense out of it at all, from ANY of the sensors. Then a quick look under the bonnet showed that the cable had been damaged by the fan.A quick resolder and all was fine. If I were you I'd check the cabling and connectors for damage or poor connections.