Oven won't come up to temp (or is very slow) (by 3 users)

Our Jenn-Air SVE47100 has functioned flawlessly since purchase and install in 1996. This past weekend, the oven failed to heat above 270 deg - or maybe I didn't wait long enough (45 minutes). Either way, it's no longer working as it used to. I hear a sequence of clicks when I'd expect the element to heat; 2 clicks about 1 second apart, then about a 5 second delay, followed by 2 more clicks. I'm guessing what little heating is occuring is happening between the clicks.

Electrically, the 2 breakers are ganged, and both appear to be OK - haven't checked them electrically, only visually. Broiler functions correctly, so I'm guessing I have 220V where it's supposed to be.

Can't say for sure (haven't tried in last couple of days), but I think burner/grill elements still function OK. Same for downdraft fan.

No error codes displayed, main controls all appear OK.

Any help or ideas would be appreciated.