We have a Frigidaire Model FEFL79FCC ceramic top oven/range unit. When you turn it on the bake mode it goes to pre-heat and starts up the top element seems to get hot first but the bottom one does finally come up to temp. Then after a few minutes the bottom element turns off the top element stays on until finally if beeps and shuts down with an F10 error code. As I under stand from multiple calls to Frigidaire this is an over temperature code. I thought it might be a resistance problem with the lower element so I purchased and installed a new lower element to no avail. It is acting like the contact for the upper element is sticking. Any suggestions?