If it's a sewer smell, you may have some unvented drains stacks. Also, if you have a drain that's rarely used (the basement floor is a popular place for these), then the water in the water trap can evaporate, allowing sewer gas in. Whether it comes in or not is a function of weather and pressure. The cure is to pour a few gallons of water down the drain ever now and then.

Mice tend to come in in the spring and fall. If you trap them, they'll smell for a few days, then as they desiccate, the small goes away.

It doesn’t smell like sewer to me but maybe it is. I don’t have a basement I’m on a slab, the smell is in the kitchen which does have two closets that hold the furnace, hot water heater, and washer/dryer. But when I smell specifically in these closets I don’t smell it in there.. it’s outside of them closer to the cupboard/gas oven area. It doesn’t smell like dead mouse.
Its strong one day, gone the next, and strong again depending on temp.
The sewer might be it if cold temps can cause downdrafts. Thank you for the input!

Have you made sure, you dont have a gas leak?

Cat_ky may be on to something...does the odor smell like rotten eggs?

https://www.angi.com/articles/my-gas-range-oven-smells-gas-when-normal.htm

It doesn’t smell like rotten eggs, more like a gross sweet trash smell. I’ll make sure I don’t have a gas leak just in case

Your gas company, should come and check it out for you.

Kelly, did you ever find the problem?

Nope not yet, it’s still coming and going randomly and still smells like a bag of trash but I can’t find anywhere that needs cleaning or where it’s coming from specifically.. my mom keeps pointing it out too she’s baffled

And you’ve ruled out the gas leak that has been suggested twice?

Pour a bit of bleach down the drains just before leaving the house for the day or just before going to bed.

It could be occasional venting from a gas/propane regulator making it hard to determine where it is coming from. A gas check will not find that either because it is part of a working system.

Do you have a water softener system? Sometimes you get that smell when the brine solution runs low?

No gas leak was found,
And I don’t have a water softener system..
I haven’t smelled it in a couple weeks, but that’s not unusual before it randomly pops up again. We will see if it comes back! Thank you for all the input

Did the smell return Kelly?