40 degree difference between left and right sides of oven

oven temperature is uneven on the left and right sides of the oven. the temperature difference is 40 degrees. What could the problem be? We have had no previous trouble with this product.

How did you measure the temperature?

Why did you decide to do it?

Gene.

[QUOTE=Gene;155553]How did you measure the temperature?

Why did you decide to do it?

Gene.[/QUOTE]
regular nothing professional Oven temperature guage. We decided to do it because whenever she bakes something it burns on the left side of the oven. we heated oven to 300 degrees and waited 15 minutes and then measured left side for 10 minutes and changed to right side and did the same.

Make sure the range is leveled properly and a cooking tray is not too large. There suppose to be enough room for the hot air to circulate around. Very often it is important to preheat the oven before cooking.

Gene.