How to fix a puffing sound when my oven is on?

that model doesn't come up,that could be the serial number,do you know that when the dryer is in self clean it gets up to 1000 degrees,when it gets this hot it can do damage to the electronics in the oven,from what i've seen on other peoples ovens i will never use the self clean again,but to answer your question remove the racks and clean them in the sink or you can soak them in the tub,whatever is easier for you.i get in there with an sos and scrub,if any spills are big on the floor i wet it and let it sit for a minute or two and scrape it out with a putty knife or you can use a spatula,if it's really bad easy off is made safe for most self clean ovens now,don't put tin foil on the oven floor when you cook,it can damage the floor,so watch out for that.kenmore doesn't make anything so you need the model number to see who made the stove,if you open the drawer under the oven door,look on the left or right side of the frame and you'll see a tag with the model and serial numbers,go here,put your model number in and you can look up the manual for your stove.hope this helps you out.
https://www.searspartsdirect.com/model/search.html?q=970C623331

The oven element has probably failed. Im not sure about your Make of oven but the oven elements are either the coil type which are positioned around the oven fan at the rear of the oven or under the oven floor. The connections for either will be at the back of the oven.

make sure the hingew are tightly secured in position by the fasteners. If you have little mechanical experience get a mechanically minded person to assist.... I enjoy getting young people to fix things for me nowadays!!!

It sounds like your oven igniiter is the problem. the part that glows in the oven. they get old after a few years and you can get a miner explosion when the burner lights. Replacing the igniter should fix this.

sounds like you have it handled...
Easy?
just a phone call away... this time , when he fixes it , watch what he does... so you can fix it next time.

Check the flame of the gas jet and make sure they are unobstructed and the flame is a steady blue. See if changing the temp affects the flame. It sounds liKe your temperature sensors might not be working. They are not that usually very expensive but trouble shoot the little things. If you have a knob control pull it and make sure that the inside is not broken just to be safe. The sensor is s usually at the left rear panel of the oven. Make sure it is intact. The other regulators would be under the floor of the oven where the gas jets are. good luck.

Put padding on the floor near by for a landing zone. Disconnect the power in the cabinet above. There are two screws in the upper cabinet that support the front. There is a wall plate that supports the back. When the two front screws are removed you will need to be supporting the microhood or it will fall. A strong assistant is nice to have. I like to have the stove out of the way so I can get under the microwave to support it. Once the front two screws are removed, tip the front down, pull the cord out of the upper cabinet. Then lift the back slightly to remove it from the channel on the wall bracket. Set it down Done.

pull your bottom drawer out and lift up on the front of the drawer then remove the drawer. then remove screws to remove the floor pan

sounds like the oven valve is leaking slightly. just as a precaution i wouldn't use it till you can get a repair man out there.