Espres

I knew about the aftermarket sensor problem so used genuine parts.

Thank you, I will check the earths and connections. The car does live outside so there might be corrosion somewhere. I can not remember the o2 sensor codes but they both related to the heater circuits.

I replaced both the front o2 sensors on my 2000 RX. Codes were cleared all ok, when going for a drive to warm up car for MOT, gearbox would not change into top gear. Took car to garage for garage owner to take to MOT station, 5 minutes later he phoned to say engine would not rev and appeared to be in limp mode. I managed to get the car home at about 5mph. I checked and codes P1663 & P1760 are showing. These can be cleared and engine runs ok with diagnostic kit plugged in. I have replaced the 2 VVT oil control valves with no change. Codes still show, and same as before faults can be cleared. Can a diagnostic unit take over as a ECU when attached? If I clear codes engine runs and revs ok but as soon as I disconnect kit engine appears to over fuel, and various things happen on the dash.

Hi On the fuel issue. Basically you can not use the fuel gauge to work out fuel consumption it is just not accurate enough, you can only do it by using a measured amount of fuel, you can do this either by draining the fuel tank and putting in a measured amount, or the easy option is to fill the tank and measure brim to brim, if you always fill to say the first or second click of the petrol pump and take a note of the mileage and litres, you will come up with fairly reliable consumption figures. Mark