Engine stumbling/surging while cruising (1 Viewer)

[BrianY]

I've got a 100 series with 225k miles. Recently, while cruising around at steady throttle, it occasionally feels like the engine stumbles or surges. I replaced the air filter, cleaned the MAF sensor and checked the battery cables. It could be my imagination, but the problem seems more common when I'm running air conditioning.

Any ideas what to check? I'm honestly not even sure if the engine at all, or a transmission issue. Not throwing any codes like a misfire.

Thanks!

 

[BrianY]

In case anyone has the same issue, this is the answer.

 

[Bradlinc]

Maybe this is obvious, but what is this?

 

[BrianY]

Maybe this is obvious, but what is this?

Ignition coil