My Whirlpool gas oven intermittantly ignites (and keeps sparking for about 5 seconds after it ignites), but then goes out. It will try to ignite again after a couple of minutes. Usually if we turn it off, and reset the oven temp and try again, it will work normally.

When it works (which is most of the time), it sparks for about 2 seconds, and stays lit.

The broiler works fine.

I replaced the oven ignitor, which didn't change a thing.

The oven is almost 2 years old. Not sure if this is related or not, but ever since we purchased it, the oven gas valve solenoid seems unusually loud. You can hear it "click" open from the next room.

What should I check next?
Thanks for your help,
Jim