Amana Range Model# ACS3350AW oven not heating, broil works great?
The first thing I would do is start with removing the oven racks, the bottom tray and pan to get access to the bake igniter. With the bottom tray removed you now can visually inspect the igniter, check to see if it is cracked or broken.
If every thing looks good set the oven to 350 and see if the igniter comes on. If it never comes on the next step is to check for 120v going to the igniter. If you have 120v going to the igniter and nothing is happening replace the igniter Part # 31940001.
There is a possability that the igniter looks to be working just fine but its not getting to the set temp needed to open the gas valve. With a good AMP meter test the igniter for the proper amperage draw. Any thing below 3 amps is not good and the igniter should be replaced.