My escort gti keeps over reving you start the engine it revs at 1500-2000 then clicks and dies to 850 what is this and is it serious we have changed the idle valve
It might be the lamda sensor. It senses the hot air gases in the exhaust pipe. If you look on the exhaust, robabley near the manifoold you should see it. It screws int ot eexhaust and has a wire coming out of it.
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