I have a Nissan Micra 5 door automatic, petrol with 45000 mileage on it. For the past seven months the check engine light comes on the dash board. It comes back after repeated erasing. The code is P0171- fuel sysm lean. Typically, the check engine light comes on after driving 6-7 miles, when the RPM is low like when pressing the throttle after stopping at a red light ( but not at all red lights and all the time) or after breaking on a speed breaker and then pressing the accelertor pedal (which is where it the MIL usually comes on), or at a variable speed when climbing a steep road or turning a corner (ocassionally). It idoes not come on (after erasing with an OBD II scanner) after starting the car, or during driving continuously. The gas mileage is OK, but I suspect it can give more mileage. The local mechanic told me that it is due to rust and dust and that the concerned component should fail completely in order to know what is throwing the code P0171. I changed fuel filter. But no effect. It does not appear to be a vacuum leak, as the CEL should come on all the time. Is it MAF sensor, throttle potentio meter? I can change the 02 sensor, if that is confirmed to be throwing the code. It has recently passed MOT test. The light is irritating and I do not want to spend hundreds of £s more hunting the problem. Any help to diagnose the problem? Can the MAF sensor be cleaned in situ (as it is not possible to pull it out due to Nissan security screws) with an electronics parts cleaner as advised by one my friends?
have the same problem?
Tuesday, January 19th, 2010 AT 11:04 AM