Oven The oven on my range is suddenly taking a LONG time to preheat. Up until last week it was fine. Cause??

There are several potential causes for a gas range being slow to preheat. Here are some troubleshooting steps you can try:

1. Check the igniter: While the igniter may be coming on, it may not be getting hot enough to ignite the gas. Make sure the igniter is clean and free from any debris or corrosion. If it is dirty, gently clean it with a soft cloth. If the igniter is damaged or not getting hot enough, it may need to be replaced.
2. Check the gas supply: Make sure that the gas supply is turned on and that the gas pressure is sufficient. If the gas pressure is too low, the oven may take longer to preheat.
3. Check the oven temperature sensor: A faulty temperature sensor can cause the oven to take longer to preheat. Use a multimeter to test the sensor for continuity. If it is not working properly, it may need to be replaced.
4. Check the oven door seal: A faulty oven door seal can cause heat to escape, making it difficult for the oven to reach the desired temperature. Inspect the seal for any cracks or gaps, and replace it if necessary.
5. Check the oven igniter safety valve: The igniter safety valve is responsible for regulating the flow of gas to the oven. If it is faulty, it may be restricting the flow of gas, causing the oven to take longer to preheat.

If you are uncomfortable performing any of these troubleshooting steps yourself, it is best to contact a qualified appliance repair technician for assistance.

The oven igniter might be weak or broken and needs replacement and the heating valve cold also needs replacement as well.

Something to do with intermittent low gas pressure? Not enough pressure to get a bigger flame.

look at this youtube video
https://www.youtube.com/watch?v=780-xxzLkuM

your bake element should get red during the preheat time and also if you leave the door open after it has preheated.
if it is not that will cause your oven to not heat right.
even if it looks ok, it could still be bad.
unplug the oven and remove the bake element, then take it to your local parts house and they can check it for you.
this is the most common problem, but it could be a problem with your oven control. try the element first.

Always preheat your oven and let it cycle at least 2 times. Your unit may show 350 but the manufactures know that it is not 350. When it registers preheated, it really means that it is at an acceptable temperature to start cooking. If you think that it may not be calibrated correctly, your owner's manual will have instructions on how to recalibrate your oven. You will be able to raise or lower the temperature by + 25 degrees or - 25 degrees. As far as the gas smell, you will from time to time smell a gas smell with a gas oven especially if you are right at it when it ignites. If you are smelling gas when it is not in use then you should be extremely concerned.

most ovens take 15-25 min to preheat.

Cold Stove, you may not be able to. The issue here is that oven manufactures put on their units a fast preheat. However it isn't possible to preheat an oven for 7 to 9 minutes and bake short time bake items properly. Also the oven sensor will respond faster than the absorbation rate of the sheet metal in the oven liner. To preheat an oven properly takes 15 to 20 minutes before putting in the food. I see this will a lot of current ovens. Sounds like a normal format of the control.

times quoted seem about right and don't suppose your old oven was much different. element ratings don't vary much for same size ovens

It sound like an igniter issue. When the igniters begin to get weak, they may still glow, but it will take several minutes till they will open the gas valve. It's easy to replace an igniter but you should be aware not to touch the black part of the new one with your fingers!!!! Good luck !!!