F3 Code Whirlpool Oven
 

I have this whirlpool oven for 10 yrs. A few years back I had a problem one time when I broiled something it locked up and we had toturn the circuit breaker off to open it up. Now recently I have been baking at temps of 350 and it seems to go to broil or just really high temps. I have read things about the oven temp sensor bar needing to be replaced. Is that difficult for the average person to do and is to expensive to replace?Thanks
Helen