Oven only reaches temp of 220 degrees.

if it is an electronic timer temp controller you might want to check it

The thermostat and control will have to be replaced

It could be either . The sensor can be checked with a good meter room temp should be around 1200ohms and change with added temp.

If you are monitoring the oven temperature with an analog style thermometer you may actually be ok, but seeing the thermometers slow reaction time.
Some newer ovens actually do pre-heat beep prior to reaching temp in an effort to conserve eelectricity.
A good home test is to try your oven at several different temps to see if there is any variation in internal temperature. Try it one day on 300, the next at 375 and another day at 450. Give your analog style thermometer time to catch up (usually just about 15 min) and leave it on for a half an hour to see if the temp maintains.
Also Beware of aluminum foil AND THE NEW OVEN LINER MATS as they can alter oven performance bay absorbing and blocking the ovens natural heat radiation and convection air flow currents that happen in all ovens, not just convection models.
Another interesting fact is that older ovens used a thermostat in them that operated much like your thermometer and was very slow to react making the oven typically about 100 degrees hotter than where the customer set it. This was just a fact of life before the advent of electronic temperature management and became noticeable when people began trying to bake older "hand me down" recipes in the newer ovens with less than stellar results.
You can mimic the older oven performance by preheating the oven about a hundred degrees higher than called for and after it reaches temp, re-set it to the correct temperature and put the items in right away.
If you find your temperatures fluctuating ask your servicer to replace first the temp sensor and as a last resort the control board as this part is usually pretty expensive.
Good Luck with this!

Put a thermomiter in the oven and set oven to 350. Once oven says it has reached temp. Give it about 15 min and check the thermomiter you placed in the oven to see if it maches.

This is where I would start.

change temp control

Hello,

You can calibrate the oven on this model. Press the bake button, adjust the bake temperature up to 550 degrees and then press and hold the bake button until a 0 displays. Now you can adjust the oven temperature up or down to match the display.

Here is a repair manual link that you can use to download frigidaire repair manuals. The one for 30 inch freestanding ranges will have the section on calibrating the oven's electronic control.

Thanks

Sears Kenmore Electric Wall OVen, Mod.#9114012192 purchased in 1993. Set oven for 425 degrees, reaches set temperature, stays on about 10 minutes and temp. display goes out and oven starts cooling down. Will not stay on desired temp.to cook. Can you tell me what my problem is? Thanks. Doug.

If this is an older oven, check to see if it has a control knob or switch labeled "manual and "hold". Make sure it's set for manual. The hold setting maintains temp at about 140 degrees.
If not the case, is this gas or electric?