2 very easy things to check/change

First is the temp sender, once they go past a predetermined level they never read right again so change it, they are around £11 from ford but you need to get the correct one for your car, not based on what the colour ring is at the top

Secondly, remove the air box so that you can access the flaps inside the air flow metres, push these flaps with your fingers to check for any resistance or unevenness in the movement

You shouldn't be able to plug then back in the wrong way either but don't discount that