Fiesta 98 ​​Failure in low when starting

Good evening everyone on the forum, I hope you can help me. I have a 1998 Ford Fiesta with a 1.3L Endura E engine, and when I start it in the mornings, it shakes a lot because the engine doesn't stay revved up. I have to rev it for a few minutes for it to reach its normal speed, and then it doesn't have any more problems. But the cold start is supposed to be controlled by the computer without me needing to rev it. My question is whether the computer is faulty, or perhaps it's a dirty or damaged sensor. If anyone has any idea what could be causing this problem or has had it with their car, please tell me how I can fix it. I look forward to your response, and thank you for your support. Have a good day

My friend, generally cold start problems are caused by a malfunction in the engine coolant temperature sensor, or the oxygen sensor, but something special can also happen with the coils and the crankshaft position sensors, but these would be basically the factors of an erratic cold start.

I would first check the temperature sensor.

Then you can check the idle air control valve, which is the stepper motor. It might be stuck since it's a '98 model; it might have the original one and it's damaged.

Check the wiring and see if the thermostat was removed during the warmer months, because now in winter it will need it since the engine needs heat!

Good luck, friend!