Oven temperature in main oven does not reach above 200 degrees. Is this a coil problem or a themostat problem?

check that the oven thermostat probe inside the oven is not close to or touching one of the upper oven elements

If the burner does not light (with a huge flame above it) I would direct you to some gas line blockage.
But if the burner flame lights good and then goes out early before it's good and hot then I would direct you to a defective oven temperature sensor. The sensor is in the upper wall of the oven cavity, can be bought at your local appliance parts store, and installed by any handyman.

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

It sounds like a weak igniter.

Try to set it at 500 degrees and see if it goes off at 350. If it does, then it probably needs calibrating. You can calibrate it by taking the knob off and finding a set screw in the stem where the knob sits. If this is not the problem, you may have to replace the thermostat. By the way, check to see if your temperature probe is not touching the wall of the oven. It will give it a false reading. Let me know if any of these things work and we will go from there.

meter the electric-220 metering the positives...110 metering 1 positive & ground at a time...Ohm the element if shows open(10 dollar multimeter doesn't move) then is bad.Can be reached from the back just above where the power attaches,for safety disconect the power

get a new oven

Try shutting off the breaker for about 10 minutes - then bring the power back on

sometimes when they get hot that is when they fail