Engine stumbling

[JustAGuy]

Ok, so I admit it's been a really long time since I worked on cars. I'm currently going to school and living in an apartment so I have no place to work on them.
Back in my gearhead days, I did everything from changing tires to swapping out engines and transmissions so I'm not a newbie to working on cars.

The issue I have is with my little POS '02 Kia spectra. In the last few weeks, it's started stumbling on acceleration at low rpm and under load. Once the RPM comes up,
the engine smooths out and gets its power back. Sometimes I'm hearing what used to sound like a bit of backfire through a carburetor. I don't believe the timing is hosed
since it runs fine once it gets a bit of RPM going. This "stumbling" and sputtering as I call it doesn't seem to be there when the engine is cold and seems to get progressively
worse as the engine warms up.

I'm thinking I may have a vacuum leak somewhere....either a hose off or possibly an intake manifold gasket leak. I seem to remember from my younger years that you could
spray something on areas that you suspected of having a vacuum leak while the engine was running and it would cause a change in RPM at idle but I can't remember what it was.
WD-40?
I initially thought maybe I got a slug of water in the gas and have run a couple tanks of gas with Heet through it and it hasn't helped.

Any ideas for a guy who hasn't worked on cars in so long that he's forgotten how to do it?
Thanks

[BPTactical]

Carb cleaner is more volatile and easily noticed for a vacuum leak. Get a vacuum diagram and make sure everything is in place. Pay particular attention to fittings on the block, with the heat hoses can crack at a fitting and be hard to find.

[ray1970]

Lol. I would guess there is a list if stuff the length if your arm that could be causing your symptoms.

[JustAGuy]

Thanks BP. Sometime soon, I'm gonna try to get a good look at all the vacuum stuff. It might be pretty obvious once I have time to get under the hood.

[BPTactical]

Lol. I would guess there is a list if stuff the length if your arm that could be causing your symptoms.

This would be a true statement. Lots of things that can cause a low end stumble.

[Wulf202]

Fuel filter. Plugs. Wires. Coils. Heet fuel treatment. Injector cleaner. Air filter. Pull codes. O2 sensors.

Off the top of my head

[Great-Kazoo]

Fuel filter. Plugs. Wires. Coils. Heet fuel treatment. Injector cleaner. Air filter. Pull codes. O2 sensors.

Off the top of my head

First thing you need to do, if you don't remember the last time it was replaced.

[trlcavscout]

EGR, I don't remember what type those use.

Is the check engine light on?

[JustAGuy]

Nope, No check engine light. I just had a tooth pulled so tomorrow, I think I'll go to the auto parts store and get the codes read. It might be something easy to find and cheap to fix.
thanks for the help all.

[trlcavscout]

Would be worth it to pay $80-$100 to have a shop diag it then fix it yourself. They may have to run it cold with a scan tool on it to catch it. Like said it could be a dozen things, most are supposes to set codes and turn on the CEL but they don't always.