Last night our Maytag oven took an hour to reach 350 degrees. I
verified that it wasn't the temperature controls by hanging a
temperature probe inside the oven. It confirmed that it was taking
that long for the oven to reach temperature.

Today, the burners light, but the oven and broiler won't light.
There's no gas being released at all.

Is there something I can do myself, or do I have to make an expensive
service call.

I will say this: we've lived in this house for 5 years, and EVERY
SINGLE Maytag appliance we bought has broken outside of warranty.

Washer, dryer, fridge, dishwasher, and now stove.