Regarding taking too long to preheat, usually you have to replace heating element, try first unplugging power cord to see if you clear F1 error.

1. Check the oven temperature sensor. The oven sensor gotsta be within spec or it will cause the F1 code. As an example of being out-of-spec, the ERC will generate an F1 fault code when the sensor shows 1650 ohms during a time-of-day mode. This is equivalent to 350°F in the oven. The resistance isn’t high enough to generate an F2 code (runaway temp) or an F3 or F4 code (shorted/open sensor circuit). The ERC monitors the sensor circuit after a heat cycle and expects the resistance to drop back to 1050-1100 ohms. The fault code is generated when this doesn’t happen. Checking the sensor circuit means also checking the harness, harness connections and the sensor itself.
2. If the oven sensor circuit checks okay, then turn your inquisitive eyeballs to the touchpad. If the range has a separate touchpad/keyboard, the keypad may have moisture that is shorting several circuits simultaneously. If the F1 code is given immediately (instead of during or after a heat cycle), remove the ribbon connector from the touchpad to the ERC after clearing the F1 code. If the F1 code does not return in five minutes, then cast a suspicious gaze upon the touchpad/keyboard. Shorts may be caused by using an ammonia-based glass cleaner. The touchpad surface will absorb ammonia-based cleaners that are sprayed directly on the glass surface. When heat is applied, the surface material can break down causing shorts. If you’re gonna use ammonia-based cleaners on your control panel, then you should spray it on the rag and then wipe the touchpanel –don’t spray directly onto the surface of the touchpad.
3. On Amana ranges with a rotary temperature dial, be sure that the knob is in the OFF position when performing tests.
4. If these tests all check good, then replace the ERC.