I've noticed that the oven has seemed slow to preheat lately, but yesterday I think we hit a tipping point. After over 20 minutes set at 400, the bottom of the oven was warm but still safe to touch with a bare hand.

The broiler works fine, as do the burners - only the main oven is at issue. Reading some of the advice on other threads, I observed the lighting process carefully, though I did not remove the bottom panel of the oven to do it. After about 30 seconds, I could see the orange glow through the openings in the bottom of the oven as usual, but it didn't actually light until about the 2-minute mark. It stayed lit for maybe 10-15 seconds, then it sounded like it went out and immediately relit. Another 10 seconds or so went by, then by the sound of it, it flickered and relit several times in quick succession. I shut it off at that point.

...I just went down to try again to check my numbers - same glow at 30-40 seconds, but this time it still hadn't lit as of 5 minutes. There was no smell of gas; I'm not sure if there was the sound of gas either - I thought I might have heard it at one point, but it was so faint that it got lost in the other sounds of the kitchen, and now I'm not sure. I was a little reluctant to stick my head in there to find out.

Other things I read suggested either the igniter or the gas regulator. The oven is about 17.5 years old. We had to replace a sensor a few years ago, but nothing beyond the lightbulb otherwise.

Any insight?

Thanks for your help!

Cool - just wanted to check before I ordered. Thanks!