Tjunlucky Posted October 22, 2016 Share Posted October 22, 2016 Recently bought a focus zetec 2005 1.6 newer shape with engine light on! Diagnosis showing both lamba sensors would these cause car to rev when idle? Car would not start the other day no spark etc crankshaft position sensor has been replaced car now starts but still revving when idle. Few weeks back on day out it did repeatedly cut out as though stalling had to get home without cruising or letting it drop to the point it would cut out. concerned has emmissions problems have put cleanant in still drags given it plenty of good runs aware lamba sensors need replacing but would that solve these issues? Is it that's needs new fuel pump? Budget is an issue and would rather spend it correctly. (Aware lamba sensors needed but keep getting told these are not the revving when idle issue) many thanks Quote Link to comment Share on other sites More sharing options...
artscot79 Posted October 23, 2016 Share Posted October 23, 2016 likely issues are the idle control valve and pcv valve till the sensors are fixed theres no point trying to find the culprit sadly youll need to do the sensors then change the idle control valve the cutting out may be due to a gearbox sensor or something else process of elimination Quote Link to comment Share on other sites More sharing options...
Tdci-Peter Posted October 23, 2016 Share Posted October 23, 2016 23 hours ago, Tjunlucky said: Diagnosis showing both lamba sensors would these cause car to rev when idle? Really you need your own decent diagnostic system. The best available for DIY use is Forscan, and costs from just £15 if you have a windows laptop. The problem is that codes have to be interpreted very carefully. For example, a code like P0131: O2 sensor Circuit low volts (Bank1, Sensor1) could be caused by air leaks into the intake or exhaust, or by a faulty throttle valve. These cause the Oxygen levels to be not as expected, and the engine has to make a guess as to the cause, and does not always get it right. The fact that you have both O2 sensors reading wrong and revving and stalling does point to either an air leak or throttle valve, rather than both O2 sensors. There are quite a few causes of air leaks, the vacuum hoses going to the brake servo, and possibly other actuators, are quite common causes. A leaking exhaust could also do it, but would be audible. If you don't have the facilities for diy, try to find a garage prepared to use experience and knowledge for proper fault finding, rather than blind reliance on DTCs. The DTCs are a vital guide, but are not always right! Quote Link to comment Share on other sites More sharing options...
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