Diagnosis
Intermittent power loss. This is almost always a loose electrical connection at the wall outlet or the range's terminal block, not an internal fault.
How to Fix It
Check the power connection first.
1. Pull the range out from the wall CAREFULLY.
2. Turn off the circuit breaker for the range.
3. Remove the outlet cover and back access panel on the range to inspect the power cord connections at the terminal block. Ensure all wires are tight and not burnt.
4. Have a licensed electrician check the 240V wall outlet for loose terminals.
If That Didn't Work
A failing oven control board can cause similar symptoms, but that's less common than a power supply issue.
Heads Up
Gas ranges still need a solid 120V electrical connection for the controls and ignition. A loose neutral wire is a frequent culprit.