I have a ford Fiesta 01 When its cold the revs drop for about 30sec to a min until it warms up?
Answers:
Probably a sensor. Could be the cold start sensor sometimes located in or near the inlet manifold
sounds like the sensor that controls the air fuel mixture. go to auto zone and see if they can scan your cars computer and find the problem.
on a cold morning your engine oil is thicker till it's been pumped round the engine warming it up. you could be using the wrong grade check your handbook.
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